Question

resolva essa equacao: -x2-2x+15=0

Answer 1

-x² - 2x + 15 = 0 .(-1)
x² + 2x - 15 = 0
Δ = 2² - 4.1.(-15)
Δ = 4 + 60
Δ = 64
x = (-2+/-√64)/2.1
x = (-2+/-8)/2
x' = (-2+8)/2 --> x' = 6/2 --> x' = 3
x" = (-2-8)/2 --> x" = -10/2 --> x" = -5