(1+x)(x-1/x²+x-1-x/x的3次方-x）
=(1+x)(x-1/x²+x-1)-(1+x)(1-x)/x的3次方-x）
=(1+x)(x-1/x(x+1)-(1+x)(1-x)/x(x+1）(x-1)
=(x-1)/x+1/x=x/x=1
3x-6/x²-4÷(x+2/x²+4x+4) -2
=3(x-2)/(x+2)(x-2)÷(x+2/(x+2)² -2
=3/(x+2)÷1/(x+2)-2
=3-2=1