Question

qual o calculo de x2-8x-20= 0?

Answer 1

x²-8x-20 = 0
Δ = (-8)² - 4.1.(-20)
Δ = 64 + 80
Δ = 144
x = [-(-8)+/-√144]/2.1
x = (8+/-12)/2
x' = (8+12)/2 = 20/2 = 10
x" = (8-12)/2 = -4/2 = -2
S: {-2; 10}