x - y = 5
(x² - y²)(x + y) = 245
(x - y)(x+y)(x+y) = 245
5(x + y)² = 245
(x + y)² = 49
1. x + y = 7
x₁ = 6 y₁ = 1
2. x + y = -7
x₂ = -1 y₂ = -6
cумма иксов -1 + 6 = 5