分解因式：①1/2a²b²+2+2ab②x³-4x③6(x-y)-9-(x-y)²④m²-2mn+n²-16

分解因式：①1/2a²b²+2+2ab②x³-4x③6(x-y)-9-(x-y)²④m²-2mn+n²-16
分解因式：①1/2a²b²+2+2ab②x³-4x③6(x-y)-9-(x-y)²④m²-2mn+n²-16

分解因式：①1/2a²b²+2+2ab②x³-4x③6(x-y)-9-(x-y)²④m²-2mn+n²-16
①1/2a²b²+2+2ab
=1/2(a²b²+4+4ab)
=1/2(ab+2)²
②x³-4x
=x(x²-4)
=x(x+2)(x-2)
③6(x-y)-9-(x-y)²
=-[(x-y)²-6(x-y)+9]
= -(x-y-3)²
④m²-2mn+n²-16
=(m-n)²-16
=(m-n+4)(m-n-4)