Question

Resolva as equações de 2° grau a seguir
a) 7x² + 13x -2 = 0
b) 3x² - 4x = 0

Answer 1

Resposta:

a) S = {1/7, -2}

b) S = {4/3, 0}

Explicação passo-a-passo:

a) 7x² + 13x - 2 = 0

a = 7; b = 13; c = -2

∆ = b² - 4 × a × c

∆ = 13² - 4 × 7 × (-2)

∆ = 169 + 56

∆ = 225

x = -b ± √∆ / 2 × a

x = -13 ± √225 / 2 × 73

x = -13 ± 15 / 14

x' = -13 + 15 / 14

x' = 2 / 14 (÷2)

x' = 1/7

x'' = -13 - 15 / 14

x'' = -28 / 14

x'' = -2

b) 3x² - 4x = 0

a = 3; b = -4; c = 0

∆ = b² - 4 × a × c

∆ = (-4)² - 4 × 3 × 0

∆ = 16 - 0

∆ = 16

x = -b ± √∆ / 2 × a

x = -(-4) ± √16 / 2 × 3

x = 4 ± 4 / 6

x' = 4 + 4 / 6

x' = 8 / 6

x' = 4/3

x'' = 4 - 4 / 6

x'' = 0 / 6

x'' = 0