如何将这些题目因式分解?a²-4ab+4b²+3a-6b-4(x²+3x-3)(x²+3x+4)-8

如何将这些题目因式分解?
a²-4ab+4b²+3a-6b-4
(x²+3x-3)(x²+3x+4)-8

a²-4ab+4b²+3a-6b-4
=(a-2b)²+3(a-2b)-4
=(a-2b-1)(a-2b+4)
(x²+3x-3)(x²+3x+4)-8
=(x²+3x)²+(x²+3x)-12-8
=(x²+3x)²+(x²+3x)-20
=(x²+3x-4)(x²+3x+5)
=(x+4)(x-1)(x²+3x+5)