Question

resolva as equações abaixo usando a formula de bhaskara
a) x²-x-20=0
b)x²-3x-4=0
c)x²-8x+7=0

Answer 1

a) ∆ = -1² - 4.1.(-20)

∆ = 1 + 80

∆ = 81

- (-1) ± √81 / 2.1

1 ± 9 / 2

x' = 1+9/2 = 10/2 = 5

x" = 1-9/2 = -8/2 = -4

b) ∆ = -3² - 4.1.(-4)

∆ = 9 + 16

∆ = 25

- (-3) ± √25 / 2.1

3 ± 5/2

x'= 3+5/2 = 8/2 = 4

x" = 3-5/2 = -2/2 = -1

c) ∆ = -8² - 4 1 7

∆ = 64 - 28

∆ = 36

- (-8) ± √36 / 2.1

8 ± 6 / 2

x' = 8+6/2 = 14/2 = 7

x" = 8-6/2 = 2/2 = 1