Question

Rozwiąż równanie:
-(x-1)x=9(x-1)

Answer 1

-(x - 1)x = 9(x - 1)
-(x² - x) = 9x - 9     |*(-1)
x² - x = -9x + 9
x² - x + 9x - 9 = 0
x² + 8x - 9 = 0
Δ = b² - 4ac = 64 + 36 = 100
√Δ = 10
x₁ = (-8-10)/2 = -9
x₂ = (-8+10)/2 = 1
x ∈ {-9, 1}