Question

!!!Alguém me ajuda!!!

a) 8x²-2x-1=0

b) 10x²-11+1=0

c) x²+5x-14=0

Answer 1

a) Δ = (-2)² - 4 × 8 × (-1)

Δ = 4 + 32

Δ = 36

x = -(-2)±√36/2×8

x = 2±6/16

x' = 2+6/16

x'' = 2-6/16

x' = 1/2 = 0,5

x" = - 1/4 = -0,25

b) Seria 10x²-11x+1=0?

Δ = (-11)² - 4 × 10 × 1

Δ = 121 - 40

Δ = 81

x = -(-11)±√81/2×10

x = 11±9/20

x' = 11+9/20

x" = 11-9/20

x' = 1

x" = 1/10 = 0,1

c) Δ = 5² - 4 × 1 × (-14)

Δ = 25 + 56

Δ = 81

x = -5±√81/2×1

x = -5±9/2

x' = -5+9/2

x" = -5-9/2

x' = 2

x" = -7