问几道因式分解题

a²（x-2a）³-b(2a-3)²
=

（x-1）²-9
=(x-1+3)(x-1-3)
=(x+2)(x-4)

(x+y)²-x²y²
=(x+y+xy)(x-y-xy)

(x+y)²-4(x+y)+1
=(x+y-2)^2-3
=(x+y-2+根号3)(x+y-2-根号3)

a³+a²
=a^2(a+1)

若ab=2,a+b=5,求a³b+2a²b²+ab³的值
a³b+2a²b²+ab³=ab(b+a)^2
=2*25
=50