eq1=x+2y==9
eq2=3x+2y==10
How to operate the multiplication of two equations to obtain:
(x+2y)(3x+2y)==90
Simplify to obtain:
3x^2+8xy+4y^2==90
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3 Answers
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I much prefer
MultiplySides[eq1, eq2] //Expand
to BobHanlon's otherwise fine solution. It also generalizes quite nicely to AddSides[].
answered Apr 18, 2023 at 0:51
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Thread[eq1 eq2, Equal]
(* (x + 2 y) (3 x + 2 y) == 90 *)
% // Expand
(* 3 x^2 + 8 x y + 4 y^2 == 90 *)
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Clear["Global`*"]
eq1 = x + 2 y == 9;
eq2 = 3 x + 2 y == 10;
eq3 = Equal @@ Times @@ (List @@@ {eq1, eq2})
(* (x + 2 y) (3 x + 2 y) == 90 *)
eq4 = eq3 // ExpandAll
(* 3 x^2 + 8 x y + 4 y^2 == 90 *)
answered Apr 18, 2023 at 0:46