$9x^2+27=9\cdot (x^2+3)=3^2\cdot (x^2+3)9x^2+27=9\backslash cdot\; (x^2+3)=3^2\backslash cdot(x^2+3)$

$6x^2+18=6\cdot (x^2+3)6x^2+18=6\backslash cdot\; (x^2+3)$

$9x^2+3=3\cdot (3x^2+1)9x^2+3=3\backslash cdot\; (3x^2+1)$