Question

Помогите пожалуйста)))))))

Answer 1

$left { {{x+2y=4} atop {-3x+y=7}} right. \ x = 4 - 2y \ -3 (4-2y) + y = 7 \ -12+6y+y = 7 \ 7y = 7+12 \ 7y = 19 \ y = frac{19}{7} \ x = 4 - 2 * frac{19}{7} \ x = 4 - frac{38}{7} \ x= frac{-10}{7}$