Question

Помогите решить на фото и вот ,
3х +4у = 0
2х + 3у = 1

И

7u + 2v =1
17u +6v + -9

7 класс.

Answer 1

$3x + 4y = 0 \ 2x + 3y = 1 \ x = - frac{4}{3} y \ 2( - frac{4}{3} y) + 3y = 1 \ 3y - frac{8}{3} y = 1 \ frac{1}{3} y = 1 \ y = 3 \ x = - frac{4}{3} y = - frac{4 times 3}{3} = - 4 \ = = = = = = = = = \ 7x + 2y = 1 \ 17x + 6y = - 9 \ y = frac{1 - 7x}{2} \ 17x + 6( frac{1 - 7x}{2} ) = - 9 \ 17x + 3 - 21x = - 9 \ 4x = 6 \ x = 1.5 \ y = frac{1 - 7x}{2} = frac{1 - 10.5}{2} = - 4.75 \ ========= \ 2x(2x + 3y) - {(x + y)}^{2} = 4 {x}^{2} + 6xy - {x}^{2} - 2xy - {y}^{2} = 3 {x}^{2} + 4xy - {y}^{2}$