Question: how do i fully factorise this the simplest way possible...

How do I fully factorise this the simplest way possible? (This is for VCE Maths Methods 1/2). I've tried and after 9 lines of working out I'm still not there yet so is there an easier solution?). Thanks in advance!

9(p-q)^(2)+12(p^(2)-q^(2))+4(p+q)^(2)