Solving y = 1/4 log(2) (8x – 56)^16 – 12












-1












$begingroup$


Hello I would like to know if whether I simplified y = 1/4 log2 (8x – 56)^16 – 12 correctly or not. Here are my steps:




  1. 12 = log2 (8x – 56)^4 => I moved the 1/4 to the power using the log laws. 1/4 x 16 equals 4. I also moved the -12 to the other side which equals +12.


  2. Log2(8x)^4 – log2(56)^4 = 12 => Since (8x-56) has the same log base I rewrote it as two terms.


  3. Log2(8x/56)^4 = 12 => Using the log laws I divided the 8x with 56.


  4. Log2(x/7)^4 = 12 => I simplified the fraction.


  5. Log2(x^4/7^4 ) = 12 => I applied the power of 4 to the fraction.


  6. 2^12 = (x^4/7^4 ) => I converted the logarithm to an exponential equation


  7. 4096/2401 = x^4 => I carried the 2401 (7^4) to the other side. Dividing the 2^12 with 7^4.


  8. ∜(4096/2401) = x => I fourth rooted both sides.


  9. x = 8/7 = I arrived with this fraction.



My question is, did I solve the equation correctly? Thank you!










share|cite|improve this question











$endgroup$












  • $begingroup$
    To be clear: Are you solving the equation $$y = frac14 log_2 (8x-56)^{16}-12$$ for $x$ when $y=0$? (BTW: One way to check your answer is to substitute it back into the original equation and see if you get what you expect.)
    $endgroup$
    – Blue
    Jan 30 at 18:33










  • $begingroup$
    This would be easier to read if you used MathJax
    $endgroup$
    – J. W. Tanner
    Jan 30 at 19:02










  • $begingroup$
    Hello Blue, the question just asks to simplify the equation.
    $endgroup$
    – moe
    Jan 30 at 23:47
















-1












$begingroup$


Hello I would like to know if whether I simplified y = 1/4 log2 (8x – 56)^16 – 12 correctly or not. Here are my steps:




  1. 12 = log2 (8x – 56)^4 => I moved the 1/4 to the power using the log laws. 1/4 x 16 equals 4. I also moved the -12 to the other side which equals +12.


  2. Log2(8x)^4 – log2(56)^4 = 12 => Since (8x-56) has the same log base I rewrote it as two terms.


  3. Log2(8x/56)^4 = 12 => Using the log laws I divided the 8x with 56.


  4. Log2(x/7)^4 = 12 => I simplified the fraction.


  5. Log2(x^4/7^4 ) = 12 => I applied the power of 4 to the fraction.


  6. 2^12 = (x^4/7^4 ) => I converted the logarithm to an exponential equation


  7. 4096/2401 = x^4 => I carried the 2401 (7^4) to the other side. Dividing the 2^12 with 7^4.


  8. ∜(4096/2401) = x => I fourth rooted both sides.


  9. x = 8/7 = I arrived with this fraction.



My question is, did I solve the equation correctly? Thank you!










share|cite|improve this question











$endgroup$












  • $begingroup$
    To be clear: Are you solving the equation $$y = frac14 log_2 (8x-56)^{16}-12$$ for $x$ when $y=0$? (BTW: One way to check your answer is to substitute it back into the original equation and see if you get what you expect.)
    $endgroup$
    – Blue
    Jan 30 at 18:33










  • $begingroup$
    This would be easier to read if you used MathJax
    $endgroup$
    – J. W. Tanner
    Jan 30 at 19:02










  • $begingroup$
    Hello Blue, the question just asks to simplify the equation.
    $endgroup$
    – moe
    Jan 30 at 23:47














-1












-1








-1





$begingroup$


Hello I would like to know if whether I simplified y = 1/4 log2 (8x – 56)^16 – 12 correctly or not. Here are my steps:




  1. 12 = log2 (8x – 56)^4 => I moved the 1/4 to the power using the log laws. 1/4 x 16 equals 4. I also moved the -12 to the other side which equals +12.


  2. Log2(8x)^4 – log2(56)^4 = 12 => Since (8x-56) has the same log base I rewrote it as two terms.


  3. Log2(8x/56)^4 = 12 => Using the log laws I divided the 8x with 56.


  4. Log2(x/7)^4 = 12 => I simplified the fraction.


  5. Log2(x^4/7^4 ) = 12 => I applied the power of 4 to the fraction.


  6. 2^12 = (x^4/7^4 ) => I converted the logarithm to an exponential equation


  7. 4096/2401 = x^4 => I carried the 2401 (7^4) to the other side. Dividing the 2^12 with 7^4.


  8. ∜(4096/2401) = x => I fourth rooted both sides.


  9. x = 8/7 = I arrived with this fraction.



My question is, did I solve the equation correctly? Thank you!










share|cite|improve this question











$endgroup$




Hello I would like to know if whether I simplified y = 1/4 log2 (8x – 56)^16 – 12 correctly or not. Here are my steps:




  1. 12 = log2 (8x – 56)^4 => I moved the 1/4 to the power using the log laws. 1/4 x 16 equals 4. I also moved the -12 to the other side which equals +12.


  2. Log2(8x)^4 – log2(56)^4 = 12 => Since (8x-56) has the same log base I rewrote it as two terms.


  3. Log2(8x/56)^4 = 12 => Using the log laws I divided the 8x with 56.


  4. Log2(x/7)^4 = 12 => I simplified the fraction.


  5. Log2(x^4/7^4 ) = 12 => I applied the power of 4 to the fraction.


  6. 2^12 = (x^4/7^4 ) => I converted the logarithm to an exponential equation


  7. 4096/2401 = x^4 => I carried the 2401 (7^4) to the other side. Dividing the 2^12 with 7^4.


  8. ∜(4096/2401) = x => I fourth rooted both sides.


  9. x = 8/7 = I arrived with this fraction.



My question is, did I solve the equation correctly? Thank you!







proof-verification logarithms






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 30 at 23:49







moe

















asked Jan 30 at 17:56









moemoe

82




82












  • $begingroup$
    To be clear: Are you solving the equation $$y = frac14 log_2 (8x-56)^{16}-12$$ for $x$ when $y=0$? (BTW: One way to check your answer is to substitute it back into the original equation and see if you get what you expect.)
    $endgroup$
    – Blue
    Jan 30 at 18:33










  • $begingroup$
    This would be easier to read if you used MathJax
    $endgroup$
    – J. W. Tanner
    Jan 30 at 19:02










  • $begingroup$
    Hello Blue, the question just asks to simplify the equation.
    $endgroup$
    – moe
    Jan 30 at 23:47


















  • $begingroup$
    To be clear: Are you solving the equation $$y = frac14 log_2 (8x-56)^{16}-12$$ for $x$ when $y=0$? (BTW: One way to check your answer is to substitute it back into the original equation and see if you get what you expect.)
    $endgroup$
    – Blue
    Jan 30 at 18:33










  • $begingroup$
    This would be easier to read if you used MathJax
    $endgroup$
    – J. W. Tanner
    Jan 30 at 19:02










  • $begingroup$
    Hello Blue, the question just asks to simplify the equation.
    $endgroup$
    – moe
    Jan 30 at 23:47
















$begingroup$
To be clear: Are you solving the equation $$y = frac14 log_2 (8x-56)^{16}-12$$ for $x$ when $y=0$? (BTW: One way to check your answer is to substitute it back into the original equation and see if you get what you expect.)
$endgroup$
– Blue
Jan 30 at 18:33




$begingroup$
To be clear: Are you solving the equation $$y = frac14 log_2 (8x-56)^{16}-12$$ for $x$ when $y=0$? (BTW: One way to check your answer is to substitute it back into the original equation and see if you get what you expect.)
$endgroup$
– Blue
Jan 30 at 18:33












$begingroup$
This would be easier to read if you used MathJax
$endgroup$
– J. W. Tanner
Jan 30 at 19:02




$begingroup$
This would be easier to read if you used MathJax
$endgroup$
– J. W. Tanner
Jan 30 at 19:02












$begingroup$
Hello Blue, the question just asks to simplify the equation.
$endgroup$
– moe
Jan 30 at 23:47




$begingroup$
Hello Blue, the question just asks to simplify the equation.
$endgroup$
– moe
Jan 30 at 23:47










2 Answers
2






active

oldest

votes


















0












$begingroup$

You had a good start. $12 = log_2 (8x – 56)^4$ can be rewritten as $12 = 4 log_2 |8x – 56|$ or $log_2 |8x – 56|=3$ which leads to $|8x-56|=8$. Can you finish?



$y+12 = log_2 (8x – 56)^4$ can be simplified to $2^{y/4}=|x-7|$.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    I can finish. Thank you! One question, instead of |8x−56| = 8, is it supposed to be |8x−56| = y + 8 since we don't know the value of y. Y is not stated to be as 0.
    $endgroup$
    – moe
    Jan 30 at 23:43










  • $begingroup$
    Also, I forgot to mention that it says to simplify. would that make any changes?
    $endgroup$
    – moe
    Jan 30 at 23:50



















0












$begingroup$

The separation you did in step 2 is not valid. Log does not distribute over subtraction. Also (though your answer is way off by then), in step 7 you divided when you meant to multiply.



You can always check your work by plugging your answer back into the original equation you were trying to solve.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    For step one, (8x-56)^16, so I brought the 1/4 to the 16 which equals 4. Since 16/4 equals 4. In this case, the equation only equals to y. So it isn't like 4=4 its the y = 1/4 log2 (8x – 56)^16 – 12. Do you understand what I mean?
    $endgroup$
    – moe
    Jan 30 at 18:08










  • $begingroup$
    Ah, sorry. I didn't notice the 16. Scrap that bit, look at step 2.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:09










  • $begingroup$
    No worries. So how do I solve the equation if I can't distribute the equation over subtraction? Do you know how? Thanks.
    $endgroup$
    – moe
    Jan 30 at 18:13










  • $begingroup$
    See Vasya's answer. At some point you need to apply the function $2^x$ to both sides.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:45












Your Answer





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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes









0












$begingroup$

You had a good start. $12 = log_2 (8x – 56)^4$ can be rewritten as $12 = 4 log_2 |8x – 56|$ or $log_2 |8x – 56|=3$ which leads to $|8x-56|=8$. Can you finish?



$y+12 = log_2 (8x – 56)^4$ can be simplified to $2^{y/4}=|x-7|$.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    I can finish. Thank you! One question, instead of |8x−56| = 8, is it supposed to be |8x−56| = y + 8 since we don't know the value of y. Y is not stated to be as 0.
    $endgroup$
    – moe
    Jan 30 at 23:43










  • $begingroup$
    Also, I forgot to mention that it says to simplify. would that make any changes?
    $endgroup$
    – moe
    Jan 30 at 23:50
















0












$begingroup$

You had a good start. $12 = log_2 (8x – 56)^4$ can be rewritten as $12 = 4 log_2 |8x – 56|$ or $log_2 |8x – 56|=3$ which leads to $|8x-56|=8$. Can you finish?



$y+12 = log_2 (8x – 56)^4$ can be simplified to $2^{y/4}=|x-7|$.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    I can finish. Thank you! One question, instead of |8x−56| = 8, is it supposed to be |8x−56| = y + 8 since we don't know the value of y. Y is not stated to be as 0.
    $endgroup$
    – moe
    Jan 30 at 23:43










  • $begingroup$
    Also, I forgot to mention that it says to simplify. would that make any changes?
    $endgroup$
    – moe
    Jan 30 at 23:50














0












0








0





$begingroup$

You had a good start. $12 = log_2 (8x – 56)^4$ can be rewritten as $12 = 4 log_2 |8x – 56|$ or $log_2 |8x – 56|=3$ which leads to $|8x-56|=8$. Can you finish?



$y+12 = log_2 (8x – 56)^4$ can be simplified to $2^{y/4}=|x-7|$.






share|cite|improve this answer











$endgroup$



You had a good start. $12 = log_2 (8x – 56)^4$ can be rewritten as $12 = 4 log_2 |8x – 56|$ or $log_2 |8x – 56|=3$ which leads to $|8x-56|=8$. Can you finish?



$y+12 = log_2 (8x – 56)^4$ can be simplified to $2^{y/4}=|x-7|$.







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited Jan 31 at 3:10

























answered Jan 30 at 18:29









VasyaVasya

4,2771618




4,2771618












  • $begingroup$
    I can finish. Thank you! One question, instead of |8x−56| = 8, is it supposed to be |8x−56| = y + 8 since we don't know the value of y. Y is not stated to be as 0.
    $endgroup$
    – moe
    Jan 30 at 23:43










  • $begingroup$
    Also, I forgot to mention that it says to simplify. would that make any changes?
    $endgroup$
    – moe
    Jan 30 at 23:50


















  • $begingroup$
    I can finish. Thank you! One question, instead of |8x−56| = 8, is it supposed to be |8x−56| = y + 8 since we don't know the value of y. Y is not stated to be as 0.
    $endgroup$
    – moe
    Jan 30 at 23:43










  • $begingroup$
    Also, I forgot to mention that it says to simplify. would that make any changes?
    $endgroup$
    – moe
    Jan 30 at 23:50
















$begingroup$
I can finish. Thank you! One question, instead of |8x−56| = 8, is it supposed to be |8x−56| = y + 8 since we don't know the value of y. Y is not stated to be as 0.
$endgroup$
– moe
Jan 30 at 23:43




$begingroup$
I can finish. Thank you! One question, instead of |8x−56| = 8, is it supposed to be |8x−56| = y + 8 since we don't know the value of y. Y is not stated to be as 0.
$endgroup$
– moe
Jan 30 at 23:43












$begingroup$
Also, I forgot to mention that it says to simplify. would that make any changes?
$endgroup$
– moe
Jan 30 at 23:50




$begingroup$
Also, I forgot to mention that it says to simplify. would that make any changes?
$endgroup$
– moe
Jan 30 at 23:50











0












$begingroup$

The separation you did in step 2 is not valid. Log does not distribute over subtraction. Also (though your answer is way off by then), in step 7 you divided when you meant to multiply.



You can always check your work by plugging your answer back into the original equation you were trying to solve.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    For step one, (8x-56)^16, so I brought the 1/4 to the 16 which equals 4. Since 16/4 equals 4. In this case, the equation only equals to y. So it isn't like 4=4 its the y = 1/4 log2 (8x – 56)^16 – 12. Do you understand what I mean?
    $endgroup$
    – moe
    Jan 30 at 18:08










  • $begingroup$
    Ah, sorry. I didn't notice the 16. Scrap that bit, look at step 2.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:09










  • $begingroup$
    No worries. So how do I solve the equation if I can't distribute the equation over subtraction? Do you know how? Thanks.
    $endgroup$
    – moe
    Jan 30 at 18:13










  • $begingroup$
    See Vasya's answer. At some point you need to apply the function $2^x$ to both sides.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:45
















0












$begingroup$

The separation you did in step 2 is not valid. Log does not distribute over subtraction. Also (though your answer is way off by then), in step 7 you divided when you meant to multiply.



You can always check your work by plugging your answer back into the original equation you were trying to solve.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    For step one, (8x-56)^16, so I brought the 1/4 to the 16 which equals 4. Since 16/4 equals 4. In this case, the equation only equals to y. So it isn't like 4=4 its the y = 1/4 log2 (8x – 56)^16 – 12. Do you understand what I mean?
    $endgroup$
    – moe
    Jan 30 at 18:08










  • $begingroup$
    Ah, sorry. I didn't notice the 16. Scrap that bit, look at step 2.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:09










  • $begingroup$
    No worries. So how do I solve the equation if I can't distribute the equation over subtraction? Do you know how? Thanks.
    $endgroup$
    – moe
    Jan 30 at 18:13










  • $begingroup$
    See Vasya's answer. At some point you need to apply the function $2^x$ to both sides.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:45














0












0








0





$begingroup$

The separation you did in step 2 is not valid. Log does not distribute over subtraction. Also (though your answer is way off by then), in step 7 you divided when you meant to multiply.



You can always check your work by plugging your answer back into the original equation you were trying to solve.






share|cite|improve this answer











$endgroup$



The separation you did in step 2 is not valid. Log does not distribute over subtraction. Also (though your answer is way off by then), in step 7 you divided when you meant to multiply.



You can always check your work by plugging your answer back into the original equation you were trying to solve.







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited Jan 30 at 18:09

























answered Jan 30 at 18:02









Nathaniel MayerNathaniel Mayer

1,863516




1,863516












  • $begingroup$
    For step one, (8x-56)^16, so I brought the 1/4 to the 16 which equals 4. Since 16/4 equals 4. In this case, the equation only equals to y. So it isn't like 4=4 its the y = 1/4 log2 (8x – 56)^16 – 12. Do you understand what I mean?
    $endgroup$
    – moe
    Jan 30 at 18:08










  • $begingroup$
    Ah, sorry. I didn't notice the 16. Scrap that bit, look at step 2.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:09










  • $begingroup$
    No worries. So how do I solve the equation if I can't distribute the equation over subtraction? Do you know how? Thanks.
    $endgroup$
    – moe
    Jan 30 at 18:13










  • $begingroup$
    See Vasya's answer. At some point you need to apply the function $2^x$ to both sides.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:45


















  • $begingroup$
    For step one, (8x-56)^16, so I brought the 1/4 to the 16 which equals 4. Since 16/4 equals 4. In this case, the equation only equals to y. So it isn't like 4=4 its the y = 1/4 log2 (8x – 56)^16 – 12. Do you understand what I mean?
    $endgroup$
    – moe
    Jan 30 at 18:08










  • $begingroup$
    Ah, sorry. I didn't notice the 16. Scrap that bit, look at step 2.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:09










  • $begingroup$
    No worries. So how do I solve the equation if I can't distribute the equation over subtraction? Do you know how? Thanks.
    $endgroup$
    – moe
    Jan 30 at 18:13










  • $begingroup$
    See Vasya's answer. At some point you need to apply the function $2^x$ to both sides.
    $endgroup$
    – Nathaniel Mayer
    Jan 30 at 18:45
















$begingroup$
For step one, (8x-56)^16, so I brought the 1/4 to the 16 which equals 4. Since 16/4 equals 4. In this case, the equation only equals to y. So it isn't like 4=4 its the y = 1/4 log2 (8x – 56)^16 – 12. Do you understand what I mean?
$endgroup$
– moe
Jan 30 at 18:08




$begingroup$
For step one, (8x-56)^16, so I brought the 1/4 to the 16 which equals 4. Since 16/4 equals 4. In this case, the equation only equals to y. So it isn't like 4=4 its the y = 1/4 log2 (8x – 56)^16 – 12. Do you understand what I mean?
$endgroup$
– moe
Jan 30 at 18:08












$begingroup$
Ah, sorry. I didn't notice the 16. Scrap that bit, look at step 2.
$endgroup$
– Nathaniel Mayer
Jan 30 at 18:09




$begingroup$
Ah, sorry. I didn't notice the 16. Scrap that bit, look at step 2.
$endgroup$
– Nathaniel Mayer
Jan 30 at 18:09












$begingroup$
No worries. So how do I solve the equation if I can't distribute the equation over subtraction? Do you know how? Thanks.
$endgroup$
– moe
Jan 30 at 18:13




$begingroup$
No worries. So how do I solve the equation if I can't distribute the equation over subtraction? Do you know how? Thanks.
$endgroup$
– moe
Jan 30 at 18:13












$begingroup$
See Vasya's answer. At some point you need to apply the function $2^x$ to both sides.
$endgroup$
– Nathaniel Mayer
Jan 30 at 18:45




$begingroup$
See Vasya's answer. At some point you need to apply the function $2^x$ to both sides.
$endgroup$
– Nathaniel Mayer
Jan 30 at 18:45


















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