Х² + (m - n)x - mn = 0
D = b² - 4ac
D = (m-n)² - 4 * 1 * (- mn) =
= m² - 2mn + n² + 4mn =
= m² + 2mn + n² = (m + n)²
√D = √(m + n)² = (m + n)
x₁ = (- (m - n) + (m + n))/2 = (- m + n + m + n)/2 = 2n/2 = n
x₂ = (- (m - n) - (m + n))/2 = (- m + n - m - n)/2 = -2m/2 = - m
Ответ: х₁ = n;
х₂ = - m