1.
5ax2+x3−5a−x=(5ax2−5a)+(x3−x)=5a(x2−1)+x(x2−1)=(x2−1)(5a+x)=(x−1)(x+1)(5a+x)
2.
a2−b2+12b−36=a2−(b2−12b+36)=a2−(b−6)2=[a−(b−6)][a+(b−6)]=(a−b+6)(a+b−6)
3.
3x3−x2y+6x2y−2xy2+3xy2−y3=x2(3x−y)+2xy(3x−y)+y2(3x−y)=(3x−y)(x2+2xy+y2)=(3x−y)(x+y)2
I hope this helped,
Gavin
+239 
