Question

x²-4x-5=0 equaçao do 2 grau me ajudem pfv

Answer 1

x² - 4x - 5 = 0
a = 1, b = - 4, c = - 5

Δ = b² - 4ac
Δ = (- 4)² - 4 . 1 . (- 5)
Δ = 16 + 20
Δ = 36

x = (- b ± √Δ)/2a
x = (- (- 4) ± √36)/2 . 1
x = (4 ± 6)/2

x' = (4 + 6)/2 = 10/2 = 5
x'' = (4 - 6)/2 = - 2/2 = - 1

x = 5, x = - 1

Answer 2

x²-4x-5=0
Δ=b²-4ac
Δ=(-4)²-4.1.(-5)
Δ= 16 +20
Δ=36

x'= -b+√Δ      4+6          10
     --------- =  ----- > x'=------ > x'=5
        2a          2.             2


x''= -b-√Δ   4 -6           -2
     --------- =------ > x''=----- > x''= -1
        2a        2.1           2

S={-1,5}