(1)(3a+2b-1)(34-2b+1)
=9a²-(2b-1)²
=9a²-4b²-1+4b
(2)(-3a-1)(3a+1)
=-9a²-1-6a
因式分解 （1）3m(2x-y)²-3mn²
=3m(2x-y+n)(2x-y-n)
（2）（x-y)³+4(y-x)
=(x-y)(x-y+2)(x-y-2)
（3）(x-2x)²+2(x²-2x)+1
=(x²-2x+1)²
=(x-1)^4
（4）4x²+2x-y-y ²
=(2x-y)(2x+y+1)
（5）2ab+1-a²-b²
=1-(a-b)²
=(1+a-b)(1-a+b)
（6）x³-2x²y-xy²+2y³
=x²(x-y)-y²(x-y)
=(x-y)(x²-y²)
=(x-y)²(x+y)