Question

решите систему y +2x =7 x-y =16

Answer 1

$(y + 2x = 7 \\(x - y = 16 \\ \\ x = 16 + y \\ y + 2(16 + y) = 7 \\ y + 32 + 2y = 7 \\ 3y = - 25 \\ y = - \frac{25}{3} = - 8 \frac{1}{3} \\ x = 16 - \frac{25}{3} = \frac{48 - 25}{3} = \frac{23}{3} = 7 \frac{2}{3}$