Question

Решить систему методом подстановки $left { {{xy=-2} atop {x+y=1}} right.$

Answer 1

ху = -2
х+у = 1

х=1-у
(1-у)*у = -2
ху= - 2
у-у^2+2=0
y^2-y-2 = 0
D=1-4*(-2) = 9
y1 = (1+3)2 = 2
y2 = (1-3)2 = -1
x1 = 1-2 = -1
x2 = 1-(-1) = 2
Ответ (-1;2) (2;-1)