Question

2) achar as raizes das equações

a)x²-x-20=0

b)x2-3x-4=0

Answer 1

a) x²-x-20=0

∆ = -1² - 4 1 -20

∆ = 1 + 80

∆ = 81

x = - (-1) ± √81 / 2.1

x = 1 ± 9 / 2

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

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

b) x²-3x-4=0

∆ = -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