因式分解：9n²-4m²-1+4m（x²-3x)²-8(x²-3x)-20（2x-y)²-(3x+y)²

因式分解：9n²-4m²-1+4m（x²-3x)²-8(x²-3x)-20（2x-y)²-(3x+y)²
因式分解：
9n²-4m²-1+4m
（x²-3x)²-8(x²-3x)-20
（2x-y)²-(3x+y)²

因式分解：9n²-4m²-1+4m（x²-3x)²-8(x²-3x)-20（2x-y)²-(3x+y)²
9n²-4m²-1+4m
=9n²-(4m²-4m+1)
=9n²-(2m-1)²
=(3n+2m-1)(3n-2m+1)
（x²-3x)²-8(x²-3x)-20
=[(x²-3x)-10][(x²-3x)+2]
=(x²-3x-10)(x²-3x+2)
=(x-5)(x+2)(x-2)(x-1)
（2x-y)²-(3x+y)²
=[(2x-y)+(3x+y)][(2x-y)-(3x+y)]
=(2x-y+3x+y)(2x-y-3x-y)
=5x(-5x-2y)
=-5x(5x+2y)