Question

(x+2)² - 3 .( x - 4 ) - (7x+8) = 2x - 7


AJUDAAA!!!!!​

Answer 1

Resposta:

x' = 3

x'' = 5

Explicação passo a passo:

(x+2)² - 3 .( x - 4 ) - (7x+8) = 2x - 7

x² + 2 . 2 . x + 4 - 3 . x - 3 . (- 4) - 7x - 8 = 2x - 7

x² + 4x + 4 - 3x + 12 - 7x - 8 = 2x - 7

x² + 4x + 4 - 3x + 12 - 7x - 8 - 2x + 7 = 0

x² + 4x - 3x - 7x - 2x + 4 + 12 - 8 + 7 = 0

x² + 4x - (3 + 7 + 2).x + 15 = 0

x² + 4x - 12x + 15 = 0

x² - 8x + 15 = 0

x = (-(-8) ± √((-8)² - 4 • 1 • 15)) / (2 • 1)

x = (8 ± √(64 - 60)) / 2

x = (8 ± √4) / 2

x = (8 ± √2²) / 2

x = (8 ± 2) / 2

x = 4 ± 1

x' = 4 - 1 = 3

x'' = 4 + 1 = 5