⑴5x(a-b)^2-3y(b-a)
=5x(a-b)^2+3y(a-b)
=(a-b)(5xa-5xb+3y)
⑵(y+1)(y^2-1)-(y+1)^3
=(y+1)^2(y-1)-(y+1)^3
=(y+1)^2(y-1-y-1)
=-2(y+1)^2
⑶2(1-x^2)+6a(x-1)^3
=-2(x+1)(x-1)+6a(x-1)^3
=(x-1)(-2x-2+6ax^2-12ax+6a)
⑷(x-m)^3(x-n)+(x-m)^2(n-x)
=(x-m)^3(x-n)-(x-m)^2(x-n)
=(x-m)^2(x-n)(x-m-1)
⑸-a(b-a)^2-ab(a-b)^2+ac(b-a)^2
=(b-a)^2(-a-ab+ac)
=-a(b-a)^2(1+b-c)