Question

решите систему уравнений.

Answer 1

Х + y = 2
Xy = - 15
Решение
X = 2 - y
y( 2 - y ) = - 15
2y - y^2 = - 15
y^2 - 2y - 15 = 0
D = 4 + 60 = 64 = 8^2
y1 = ( 2 + 8 ) : 2 = 5
y2 = ( 2 - 8 ) : 2 = - 3
X = 2 - y
X1 = 2 - 5 = - 3
X2 = 2 + 3 = 5
Ответ ( - 3 ; 5 ) ; ( 5 ; - 3 )