Question

x(x + 4) + x(x + 2) = 2x² + 12

Answer 1

X²+4x+x²+2x=2x²+12
X²+x²-2x²+4x+2x-12
2x²-2x²6x-12
6x-12=0

6x=12
X=12/6
X=2

Answer 2

$x(x + 4) + x(x + 2) = 2x^2 + 12 \\ \\ x^{2} +4x + x^{2} +2x = 2x^{2} +12 \\ \\ x^{2} +4x + x^{2} +2x -2x^{2} -12 = 0 \\ \\ 2x^2 -2x^2 +4x + 2x -12 = 0 \\ \\ 6x - 12 = 0 \\ \\ 6x = 12 \\ \\ x = \frac{12}{6} \\ \\ x = 2$