Question

3) Resolva as equações a seguir:
a) 3x (x+2) = 0 -
b)x (2x + 5) = 2x​

Answer 1

a)

$3x(x + 2) = 0 \\ x \times (x + 2) = 0 \\ \\ x = 0 \\ x + 2 = 0 \\ \\ x = 0 \\ x = - 2 \\ \\ x_{1} = - 2 \: . \: x_{2} = 0$

b)

$x (2x + 5) = 2x \\ {2x}^{2} + 5x = 2x \\ {2x}^{2} + 5x - 2x = 0 \\ {2x}^{2} + 3x = 0 \\ x \times (2x + 3) = 0 \\ \\ x = 0 \\ 2x + 3 = 0 \\ \\ x = 0 \\ x = - \frac{3}{2} \\ \\ x_{1} = - \frac{3}{2} . \: x_{2} = 0$

Espero que ajude!