Answer
$x=-\frac{2}{3}$
Work Step by Step
$3(x^{2}+4)+5=-6(x^{2}+2x)+13$
$3x^{2}+12+5=-6x^{2}-12x+13$
$3x^{2}+17=-6x^{2}-12x+13$
$3x^{2}+6x^{2}+12x+17-13=0$
$9x^{2}+12x+4=0$
$9x^{2}+6x+6x+4=0$
$3x(3x+2)+2(3x+2)=0$
$(3x+2)(3x+2)=0$
$x=-\frac{2}{3}$ and $x=-\frac{2}{3}$