Question

помогите решить систему уравнений
x²-y²=91
y+x=-7

Answer 1

x^2 - y^2 = 91
y = - 7 - x

x^2 - (-7 - x)^2 = 91
x^2 - (49 + 14x+  x^2) - 91 = 0 
x^2 - 49 - 14x - x^2 - 91 = 0 
- 14x - 140 = 0 
- 14x = 140
14x = - 140
x = - 10

y = - x - 7 = 10 - 7 = 3 

Ответ
( - 10; 3)