①原式=(ab)²-4ab+2²=(ab-2)²
②原式=(xy)²-8xy+4²=(xy-4)²
③原式=(x+y)²+6(x+y)+3²=(x+y+3)²
④原式=a²-2ab-2ac+b²+c²+2bc
=(a-b)²+2c(b-a)
=(a-b)(a-b-2c)
⑤原式=3(x²-2x+1)=3(x-1)²
⑥原式=x³(x²-y²)=x³(x+y)(x-y)
⑦原式=x(16x^4+8x²y²+y^4)
=x[(4x²)²+8x²y²+(y²)²]
=x(4x²+y²)²
⑧原式=(4x²)²-(y²)²
=(4x²+y²)(4x²-y²)
=(4x²+y²)(2x+y)(2x-y)
以上为解答,完全正确