Помогите решить систему xy-x=4 2x+y=7

Question

Помогите решить систему

xy-x=4
2x+y=7

Answer 1

Xy - x = 4
{ 2x + y = 7 => y = 7 - 2x

x*(7 - 2x) - x = 4
7x - 2x^2 - x = 4
2x^2 - 6x + 4 = 0 (:2)
x^2 - 3x + 2 = 0
x1 = -2
x2 = -1
y1 = 7 - 2x1 = 7 - 2*(-2) = 11
y2 = 7 - 2x2 = 7 - 2*(-1) = 9