Question

Система х2-у2=-40
Х+у=4

Answer 1

Х^2 - y^2 = - 40
X + y = 4
••••••••••
y = 4 - x
- y^2 = - ( 16 - 8x + x^2 ) = - 16 + 8x - x^2
••••••••••
X^2 - 16 + 8x - x^2 = - 40
8x = - 40 + 16
X = - 24 : 8
X = - 3
y = 4 + 3 = 7
Ответ ( - 3 ; 7 )