Question

I) identifique os coeficientes a,b e c
II) calcule o discriminante b²-4ac
III) determine o valor de x1 e x2 (raizes)

Answer 1

Resposta:

a) a = 1  | b = -3  | c = -4

b) 25

c) x' = 4  | x" = -1

Explicação passo a passo:

I)

( x + 1) . (x - 1) = 3x + 3

x² - x + x - 1 = 3x + 3

x² - 1 - 3x - 3 = 0

x² -3x - 4 = 0

a = 1  | b = -3  | c = -4

II)

(-3)² - 4 . 1 . (-4)

9 - 4 . (-4)

9 + 16

25

III)

$\frac{3 +/- \sqrt{(-3)^{2} - 4 . 1 . (-4) } }{2.1} \\\\\frac{3 +/- \sqrt{9 - 4 . (-4)} }{2}\\\\\frac{3+/- \sqrt{9+16} }{2}\\\\\frac{3+/- \sqrt{25} }{2}\\\\\frac{3+/- 5}{2}\\\\x' = \frac{3+5}{2} = \frac{8}{2} = 4\\\\x" = \frac{3-5}{2} = \frac{-2}{2} = -1$

BONS ESTUDOS!!!!