Solving an equation for 3 unknowns












0












$begingroup$


So I have the function $y=-a(x+b)^2+c$
And I also know that this equation goes through these three points
$(0,0), (6,12), (2,8)$
I tried to make a system with $3$ equations from this info, but I was unable to solve it.










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$endgroup$








  • 1




    $begingroup$
    Which equation system do you find?
    $endgroup$
    – Dr. Sonnhard Graubner
    Jan 30 at 16:04






  • 1




    $begingroup$
    Welcome to MSE. Please show us the three equations you came up with, and your attempt at solving them. Otherwise, you're just asking for someone to do your homework, which is not what this site is about.
    $endgroup$
    – saulspatz
    Jan 30 at 16:07










  • $begingroup$
    If you want to see my scribbles all over pages to solve it ur welcome just ask for it
    $endgroup$
    – user655941
    Jan 30 at 17:18
















0












$begingroup$


So I have the function $y=-a(x+b)^2+c$
And I also know that this equation goes through these three points
$(0,0), (6,12), (2,8)$
I tried to make a system with $3$ equations from this info, but I was unable to solve it.










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    Which equation system do you find?
    $endgroup$
    – Dr. Sonnhard Graubner
    Jan 30 at 16:04






  • 1




    $begingroup$
    Welcome to MSE. Please show us the three equations you came up with, and your attempt at solving them. Otherwise, you're just asking for someone to do your homework, which is not what this site is about.
    $endgroup$
    – saulspatz
    Jan 30 at 16:07










  • $begingroup$
    If you want to see my scribbles all over pages to solve it ur welcome just ask for it
    $endgroup$
    – user655941
    Jan 30 at 17:18














0












0








0





$begingroup$


So I have the function $y=-a(x+b)^2+c$
And I also know that this equation goes through these three points
$(0,0), (6,12), (2,8)$
I tried to make a system with $3$ equations from this info, but I was unable to solve it.










share|cite|improve this question











$endgroup$




So I have the function $y=-a(x+b)^2+c$
And I also know that this equation goes through these three points
$(0,0), (6,12), (2,8)$
I tried to make a system with $3$ equations from this info, but I was unable to solve it.







functions systems-of-equations graphing-functions






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Jan 30 at 17:22









the_fox

2,90231538




2,90231538










asked Jan 30 at 16:03









user655941user655941

11




11








  • 1




    $begingroup$
    Which equation system do you find?
    $endgroup$
    – Dr. Sonnhard Graubner
    Jan 30 at 16:04






  • 1




    $begingroup$
    Welcome to MSE. Please show us the three equations you came up with, and your attempt at solving them. Otherwise, you're just asking for someone to do your homework, which is not what this site is about.
    $endgroup$
    – saulspatz
    Jan 30 at 16:07










  • $begingroup$
    If you want to see my scribbles all over pages to solve it ur welcome just ask for it
    $endgroup$
    – user655941
    Jan 30 at 17:18














  • 1




    $begingroup$
    Which equation system do you find?
    $endgroup$
    – Dr. Sonnhard Graubner
    Jan 30 at 16:04






  • 1




    $begingroup$
    Welcome to MSE. Please show us the three equations you came up with, and your attempt at solving them. Otherwise, you're just asking for someone to do your homework, which is not what this site is about.
    $endgroup$
    – saulspatz
    Jan 30 at 16:07










  • $begingroup$
    If you want to see my scribbles all over pages to solve it ur welcome just ask for it
    $endgroup$
    – user655941
    Jan 30 at 17:18








1




1




$begingroup$
Which equation system do you find?
$endgroup$
– Dr. Sonnhard Graubner
Jan 30 at 16:04




$begingroup$
Which equation system do you find?
$endgroup$
– Dr. Sonnhard Graubner
Jan 30 at 16:04




1




1




$begingroup$
Welcome to MSE. Please show us the three equations you came up with, and your attempt at solving them. Otherwise, you're just asking for someone to do your homework, which is not what this site is about.
$endgroup$
– saulspatz
Jan 30 at 16:07




$begingroup$
Welcome to MSE. Please show us the three equations you came up with, and your attempt at solving them. Otherwise, you're just asking for someone to do your homework, which is not what this site is about.
$endgroup$
– saulspatz
Jan 30 at 16:07












$begingroup$
If you want to see my scribbles all over pages to solve it ur welcome just ask for it
$endgroup$
– user655941
Jan 30 at 17:18




$begingroup$
If you want to see my scribbles all over pages to solve it ur welcome just ask for it
$endgroup$
– user655941
Jan 30 at 17:18










2 Answers
2






active

oldest

votes


















0












$begingroup$

Hint: The system is given by
$$0=-a(0+b)^2+c$$
$$12=-a(6+b)^2+c$$
$$8=-a(2+b)^2+c$$
From the first equation we get $$c=ab^2$$ plugging this in equation (2) and (3) and solving for $$a$$ we get
$$frac{8}{b^2-(2+b)^2}=a=frac{12}{b^2-(6+b)^2}$$
Can you finish now?
Simplifying we get
$$2(12b+36)=3(4b+4)$$ This equation must be solved for $b$, it is linear in $$b$$






share|cite|improve this answer











$endgroup$













  • $begingroup$
    Yes i tried to solve those for finding the a b and c but i was unable to do so
    $endgroup$
    – user655941
    Jan 30 at 17:17



















0












$begingroup$

Hint:



Find quadratic polynomials $p(x)$, $q(x)$, $r(x)$ such that
begin{align}begin{cases}
p(6)=p(2)=0 ,\
p(0)=1,
end{cases}qquadbegin{cases}
q(0)=q(6)=0 ,\
q(2)=1,
end{cases} qquadbegin{cases}
r(2)=r(0)=0 ,\
r(6)=1,
end{cases} end{align}

and take
$$y(x)=0cdot p(x)+ 8cdot q(x)+12 cdot r(x).$$



Then $-b:$ is the abscissa of the axis if symmetry of the resulting parabola.






share|cite|improve this answer









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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    0












    $begingroup$

    Hint: The system is given by
    $$0=-a(0+b)^2+c$$
    $$12=-a(6+b)^2+c$$
    $$8=-a(2+b)^2+c$$
    From the first equation we get $$c=ab^2$$ plugging this in equation (2) and (3) and solving for $$a$$ we get
    $$frac{8}{b^2-(2+b)^2}=a=frac{12}{b^2-(6+b)^2}$$
    Can you finish now?
    Simplifying we get
    $$2(12b+36)=3(4b+4)$$ This equation must be solved for $b$, it is linear in $$b$$






    share|cite|improve this answer











    $endgroup$













    • $begingroup$
      Yes i tried to solve those for finding the a b and c but i was unable to do so
      $endgroup$
      – user655941
      Jan 30 at 17:17
















    0












    $begingroup$

    Hint: The system is given by
    $$0=-a(0+b)^2+c$$
    $$12=-a(6+b)^2+c$$
    $$8=-a(2+b)^2+c$$
    From the first equation we get $$c=ab^2$$ plugging this in equation (2) and (3) and solving for $$a$$ we get
    $$frac{8}{b^2-(2+b)^2}=a=frac{12}{b^2-(6+b)^2}$$
    Can you finish now?
    Simplifying we get
    $$2(12b+36)=3(4b+4)$$ This equation must be solved for $b$, it is linear in $$b$$






    share|cite|improve this answer











    $endgroup$













    • $begingroup$
      Yes i tried to solve those for finding the a b and c but i was unable to do so
      $endgroup$
      – user655941
      Jan 30 at 17:17














    0












    0








    0





    $begingroup$

    Hint: The system is given by
    $$0=-a(0+b)^2+c$$
    $$12=-a(6+b)^2+c$$
    $$8=-a(2+b)^2+c$$
    From the first equation we get $$c=ab^2$$ plugging this in equation (2) and (3) and solving for $$a$$ we get
    $$frac{8}{b^2-(2+b)^2}=a=frac{12}{b^2-(6+b)^2}$$
    Can you finish now?
    Simplifying we get
    $$2(12b+36)=3(4b+4)$$ This equation must be solved for $b$, it is linear in $$b$$






    share|cite|improve this answer











    $endgroup$



    Hint: The system is given by
    $$0=-a(0+b)^2+c$$
    $$12=-a(6+b)^2+c$$
    $$8=-a(2+b)^2+c$$
    From the first equation we get $$c=ab^2$$ plugging this in equation (2) and (3) and solving for $$a$$ we get
    $$frac{8}{b^2-(2+b)^2}=a=frac{12}{b^2-(6+b)^2}$$
    Can you finish now?
    Simplifying we get
    $$2(12b+36)=3(4b+4)$$ This equation must be solved for $b$, it is linear in $$b$$







    share|cite|improve this answer














    share|cite|improve this answer



    share|cite|improve this answer








    edited Jan 30 at 17:22

























    answered Jan 30 at 16:11









    Dr. Sonnhard GraubnerDr. Sonnhard Graubner

    78.4k42867




    78.4k42867












    • $begingroup$
      Yes i tried to solve those for finding the a b and c but i was unable to do so
      $endgroup$
      – user655941
      Jan 30 at 17:17


















    • $begingroup$
      Yes i tried to solve those for finding the a b and c but i was unable to do so
      $endgroup$
      – user655941
      Jan 30 at 17:17
















    $begingroup$
    Yes i tried to solve those for finding the a b and c but i was unable to do so
    $endgroup$
    – user655941
    Jan 30 at 17:17




    $begingroup$
    Yes i tried to solve those for finding the a b and c but i was unable to do so
    $endgroup$
    – user655941
    Jan 30 at 17:17











    0












    $begingroup$

    Hint:



    Find quadratic polynomials $p(x)$, $q(x)$, $r(x)$ such that
    begin{align}begin{cases}
    p(6)=p(2)=0 ,\
    p(0)=1,
    end{cases}qquadbegin{cases}
    q(0)=q(6)=0 ,\
    q(2)=1,
    end{cases} qquadbegin{cases}
    r(2)=r(0)=0 ,\
    r(6)=1,
    end{cases} end{align}

    and take
    $$y(x)=0cdot p(x)+ 8cdot q(x)+12 cdot r(x).$$



    Then $-b:$ is the abscissa of the axis if symmetry of the resulting parabola.






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      Hint:



      Find quadratic polynomials $p(x)$, $q(x)$, $r(x)$ such that
      begin{align}begin{cases}
      p(6)=p(2)=0 ,\
      p(0)=1,
      end{cases}qquadbegin{cases}
      q(0)=q(6)=0 ,\
      q(2)=1,
      end{cases} qquadbegin{cases}
      r(2)=r(0)=0 ,\
      r(6)=1,
      end{cases} end{align}

      and take
      $$y(x)=0cdot p(x)+ 8cdot q(x)+12 cdot r(x).$$



      Then $-b:$ is the abscissa of the axis if symmetry of the resulting parabola.






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        Hint:



        Find quadratic polynomials $p(x)$, $q(x)$, $r(x)$ such that
        begin{align}begin{cases}
        p(6)=p(2)=0 ,\
        p(0)=1,
        end{cases}qquadbegin{cases}
        q(0)=q(6)=0 ,\
        q(2)=1,
        end{cases} qquadbegin{cases}
        r(2)=r(0)=0 ,\
        r(6)=1,
        end{cases} end{align}

        and take
        $$y(x)=0cdot p(x)+ 8cdot q(x)+12 cdot r(x).$$



        Then $-b:$ is the abscissa of the axis if symmetry of the resulting parabola.






        share|cite|improve this answer









        $endgroup$



        Hint:



        Find quadratic polynomials $p(x)$, $q(x)$, $r(x)$ such that
        begin{align}begin{cases}
        p(6)=p(2)=0 ,\
        p(0)=1,
        end{cases}qquadbegin{cases}
        q(0)=q(6)=0 ,\
        q(2)=1,
        end{cases} qquadbegin{cases}
        r(2)=r(0)=0 ,\
        r(6)=1,
        end{cases} end{align}

        and take
        $$y(x)=0cdot p(x)+ 8cdot q(x)+12 cdot r(x).$$



        Then $-b:$ is the abscissa of the axis if symmetry of the resulting parabola.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 30 at 17:39









        BernardBernard

        123k741117




        123k741117






























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