5a^2(x-y)+10a(y-x)
=5a^2(x-y)-10a(x-y)
=5a(x-y)(a-2)
a(x-3)(y-2)+b(3-x)(2-y)
=a(x-3)(y-2)+b(x-3)(y-2)
=(x-3)(y-2)(a+b)
x^2+y^2/9-2/3 xy
=(x-y/3)^2
(m^2+1)^2+4m(m^+1)+4m^2
=(m^2+1+2m)^2
=(m+1)^4
8ax+12ay-10bx-15by
=(8ax+12ay)-(10bx+15by)
=4a(2x+3y)-5b(2x+3y)
=(2x+3y)(4a-5b)
2ab-a^2-b^2+4
=4-(a^2-2ab+b^2)
=2^2-(a-b)^2
=(2+a-b)(2-a+b)