How to solve the following system of equations?












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$left{ begin{aligned} xy + 2x + 2y &= -8\ yz + 2y + 2z &= 24\ xz + 2x + 2z &= -11 end{aligned} right.$
I need to solve it over the set of real numbers.










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    0












    $begingroup$


    $left{ begin{aligned} xy + 2x + 2y &= -8\ yz + 2y + 2z &= 24\ xz + 2x + 2z &= -11 end{aligned} right.$
    I need to solve it over the set of real numbers.










    share|cite|improve this question











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      0








      0


      1



      $begingroup$


      $left{ begin{aligned} xy + 2x + 2y &= -8\ yz + 2y + 2z &= 24\ xz + 2x + 2z &= -11 end{aligned} right.$
      I need to solve it over the set of real numbers.










      share|cite|improve this question











      $endgroup$




      $left{ begin{aligned} xy + 2x + 2y &= -8\ yz + 2y + 2z &= 24\ xz + 2x + 2z &= -11 end{aligned} right.$
      I need to solve it over the set of real numbers.







      systems-of-equations quadratics symmetric-polynomials






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      edited Jan 2 at 12:49









      Harry Peter

      5,47111439




      5,47111439










      asked Dec 30 '18 at 19:25









      Krisztián KissKrisztián Kiss

      313




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          2 Answers
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          Note that $$(x+2)(y+2)=xy+2x+2y+4$$Hence, our system of equations becomes $$(x+2)(y+2)=-4$$$$(y+2)(z+2)=28$$$$(x+2)(z+2)=-7$$Can you solve from here?






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            $begingroup$

            Elimimating the variable $x$ from (1) and plug this in (3) we get
            $$-frac{2 (y+4) z}{y+2}-frac{4 (y+4)}{y+2}+2 z+11=0$$
            Now we get $z$ from (2) $$z=-frac{2 (y-12)}{y+2}$$ finally we obtain one equation in $y$ factorizing we get $$frac{7 (y-2) (y+6)}{(y+2)^2}=0$$ From here we find the Solutions of our System.






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              2 Answers
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              2 Answers
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              5












              $begingroup$

              Note that $$(x+2)(y+2)=xy+2x+2y+4$$Hence, our system of equations becomes $$(x+2)(y+2)=-4$$$$(y+2)(z+2)=28$$$$(x+2)(z+2)=-7$$Can you solve from here?






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                5












                $begingroup$

                Note that $$(x+2)(y+2)=xy+2x+2y+4$$Hence, our system of equations becomes $$(x+2)(y+2)=-4$$$$(y+2)(z+2)=28$$$$(x+2)(z+2)=-7$$Can you solve from here?






                share|cite|improve this answer









                $endgroup$
















                  5












                  5








                  5





                  $begingroup$

                  Note that $$(x+2)(y+2)=xy+2x+2y+4$$Hence, our system of equations becomes $$(x+2)(y+2)=-4$$$$(y+2)(z+2)=28$$$$(x+2)(z+2)=-7$$Can you solve from here?






                  share|cite|improve this answer









                  $endgroup$



                  Note that $$(x+2)(y+2)=xy+2x+2y+4$$Hence, our system of equations becomes $$(x+2)(y+2)=-4$$$$(y+2)(z+2)=28$$$$(x+2)(z+2)=-7$$Can you solve from here?







                  share|cite|improve this answer












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                  share|cite|improve this answer










                  answered Dec 30 '18 at 19:29









                  Don ThousandDon Thousand

                  4,271734




                  4,271734























                      1












                      $begingroup$

                      Elimimating the variable $x$ from (1) and plug this in (3) we get
                      $$-frac{2 (y+4) z}{y+2}-frac{4 (y+4)}{y+2}+2 z+11=0$$
                      Now we get $z$ from (2) $$z=-frac{2 (y-12)}{y+2}$$ finally we obtain one equation in $y$ factorizing we get $$frac{7 (y-2) (y+6)}{(y+2)^2}=0$$ From here we find the Solutions of our System.






                      share|cite|improve this answer









                      $endgroup$


















                        1












                        $begingroup$

                        Elimimating the variable $x$ from (1) and plug this in (3) we get
                        $$-frac{2 (y+4) z}{y+2}-frac{4 (y+4)}{y+2}+2 z+11=0$$
                        Now we get $z$ from (2) $$z=-frac{2 (y-12)}{y+2}$$ finally we obtain one equation in $y$ factorizing we get $$frac{7 (y-2) (y+6)}{(y+2)^2}=0$$ From here we find the Solutions of our System.






                        share|cite|improve this answer









                        $endgroup$
















                          1












                          1








                          1





                          $begingroup$

                          Elimimating the variable $x$ from (1) and plug this in (3) we get
                          $$-frac{2 (y+4) z}{y+2}-frac{4 (y+4)}{y+2}+2 z+11=0$$
                          Now we get $z$ from (2) $$z=-frac{2 (y-12)}{y+2}$$ finally we obtain one equation in $y$ factorizing we get $$frac{7 (y-2) (y+6)}{(y+2)^2}=0$$ From here we find the Solutions of our System.






                          share|cite|improve this answer









                          $endgroup$



                          Elimimating the variable $x$ from (1) and plug this in (3) we get
                          $$-frac{2 (y+4) z}{y+2}-frac{4 (y+4)}{y+2}+2 z+11=0$$
                          Now we get $z$ from (2) $$z=-frac{2 (y-12)}{y+2}$$ finally we obtain one equation in $y$ factorizing we get $$frac{7 (y-2) (y+6)}{(y+2)^2}=0$$ From here we find the Solutions of our System.







                          share|cite|improve this answer












                          share|cite|improve this answer



                          share|cite|improve this answer










                          answered Dec 30 '18 at 19:38









                          Dr. Sonnhard GraubnerDr. Sonnhard Graubner

                          73.6k42864




                          73.6k42864






























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