(x²-2x)(x²-2x+2)+1=(x²-2x)²+2(x²-2x)+1=(x²-2x+1)²=(x-1)的4次方2(a²+b²)(a+b)²-(a²-b²)²=2(a²+b²)(a+b)²-(a+b)²(a-b)
...第一个没看懂= =第一个没看懂= =令x²-2x=a(x²-2x)(x²-2x+2)+1=a(a+2)+1=a²+2a+1=(a+1)²=(x²-2x+1)²=[(x-1)²]²=(x-1)的4次方