Question

04. Resolva:
a) 3x2 - 48 = 0
b) 2x2 + 6x = 0
c) 7x2 = 14x
d) 4x2 - 36 = 0​

Answer 1

Resposta:

Explicação passo-a-passo:

a) 3x² - 48 = 0  => 3x²  =  48  =>

$x^{2} =\frac{48}{3} => x^{2} =16=> x^{} =\sqrt{16} => \\x_{1} = +4 \\x_{2} = -4$

b) 2x² + 6x = 0  => => 2x( x + 3) = 0

$x_{1} = 2x = 0 => x_{1} => x = \frac{0}{2} => x_{1} = 0\\\\x_{2} = x+3 = 0 => x_{2} => x = -3 => x_{2} = -3$

c) 7x² = 14x  => 7x² - 14x = 0 => 7x(x - 2) =0

$x_{1} = 7x = 0 => x_{1} => x = \frac{0}{7} => x_{1} = 0\\\\x_{2} = x - 2 = 0 => x_{2} => x = 2 => x_{2} = 2$

d) 4x² - 36 = 0​

$x^{2} =\frac{36}{4} => x^{2} =9=> x^{} =\sqrt{9} => \\x_{1} = +3 \\x_{2} = -3$