Х1+х2=5
Х1×х2=-3
Х1^4+х2^4

Обозначу x1 = x и х2 = у.

x+y=5

xy = -3

x⁴ + y⁴ = x⁴ + 2x²y² + y⁴ - 2x²y² = (x²+y²)² - 2x²y² =

=((x+y)² - 2xy)² - 2x²y² = (25+6)² - 2 * 9 = 943