Question 1138306
{{{9-12X+6Y}}}

you have 
{{{9=3*highlight(3)}}}
{{{12=2*2*highlight(3)}}}
{{{6=2*highlight(3)}}}

=>the greatest common factor of all is {{{highlight(3)}}}

so, factor out  {{{3}}} and you have:

{{{9-12X+6Y=highlight(3)(3-4X+2Y)}}}