Решите систему уравнений!
y=x-5
y²+yx-x²-4x = - 9

Y = x - 5Y^2 + yx - x^2 - 4x = - 9X^2 - 10x + 25 + x • ( x - 5 ) - x^2 - 4x = - 9 - 14x + 25 + x^2 - 5x + 9 = 0 X^2 - 19x + 34 = 0 D = 361 - 136 = 225 ; V D = 15 X1 = ( 19 + 15 ) : 2 = 17 X2 = ( 19 - 15 ) : 2 = 2Y = x - 5 Y1 = 17 - 5 = 12 Y2 = 2 - 5 = - 3 Ответ ( 17 ; 12 ) ; ( 2 ; - 3 )