Question

Розв'язать систему ривнянь {2(x+y)-3(x-y)=3 3(x+y)-2(x-y)=7

Answer 1

$x = - 3 + 5y \\ 3(x + y) - 2(x - y) = 7 \\ \\ 3( - 3 + 5y + y) - 2( - 3 + 5y - y) = 7 \\ \\ y = 1 \\ \\ x = - 3 + 5 \times 1 = 2 \\ \\ (x \: \: \: y) = (2 \: \: \: 1) \\ \\ 2(2 + 1) - 3(2 - 1) = 3 \\ 3(2 + 1) - 2(2 - 1) = 7 \\ \\ 3 = 3 \\ 7 = 7 \\ \\ (x \: \: \: y) = (2 \: \: \: 1)$