Question

x²-2x-8=0 resolva as seguintes equação

Answer 1

x^2 - 2x - 8 = 0
a=1; b = - 2; c = - 8
∆ = b ^2 - 4ac
∆ = (-2)^2 - 4.1.(-8)
∆ = 4 + 32
∆= 36

x = [ - b +/- √∆]/2a
x = [ -(-2) +/-√36]/2.1

x' = [2 + 6]/2 = 8/2 = 4
x" = [2 - 6]/2 = - 4/2= - 2

R.: ( 4; - 2)