Question

1. Calcule, quando existirem, as raízes reais das equações
a) 2x2 + 4x = 0
c) x2 – 1 = 0
b) -5x2 = 0
d) 6x2 – 9x = 0

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Answer 1

Resposta:

a) 2x² + 4x = 0

  2x(x + 2) = 0

2x = 0

x' = 0/2

x' = 0

c) x² – 1 = 0

x² = 1

$x = \pm \sqrt{1} \\x = \pm 1$

$x_1 = -\, 1$

$x_2 = 1$

b) -5x² = 0  --> x (-1) temos:

5x² = 0

x² = 0/5

x² = 0

$x = \sqrt{0}$

$x_1 =x_2 = 0$

d) 6x² – 9x = 0

3x(2x - 3) =0

3x = 0

x' = 0/3

x' = 0

(2x - 3) =0

2x - 3 = 0

2x = 3

x" =3/2