计算(过程)
1.x^(n)-0.5x^(n+1)-0.2x^(n)+x^(n+1)-0.3x^(n+1)
2.(a+b)(a-2b)-(a+2b)(a-b)
3.5x(x^2+2x+1)-(2x+3)(x-5)
4.(m+n)(m^2+n^2)(n-m)
5.(1/2b+2a)^2(2a-1/2b)^2
6.(x-y+z)^2-(z+y-z)^2
7.[(2x+y)^2-(2x+y)(2x-y)]/2y-1/2y

要好好学习呀，
1.x^(n)-0.5x^(n+1)-0.2x^(n)+x^(n+1)-0.3x^(n+1)
=x^(n)[1-0.5x-0.2+x-0.3x)= x^(n)[0.8-0.8x]
=0.8x^(n)-0.8x^(n+1)
2.(a+b)(a-2b)-(a+2b)(a-b)
=a＾-2ab+ab-2b＾-a＾+ab-2ab+2b＾
=-2ab
3. 5x(x^2+2x+1)-(2x+3)(x-5)
=5x(x^2+2x+1)-(2x＾-7x-15)
=5x＾3+10x＾+5x-2x＾+7x+15
=5x＾3+8x＾+12x+15

4.(m+n)(m^2+n^2)(n-m)
=(n＾-m＾)(n＾+m＾)=n＾4-m＾4
5.(1/2b+2a)^2(2a-1/2b)^2
=[4a＾-1/4b＾]＾
6.(x-y+z)^2-(x+y-z)^2
=(x-y+z+x+y-z)(x-y+z-x-y+z)
=4x×(z-y)
7.[(2x+y)^2-(2x+y)(2x-y)]/2y-1/2y
=[(2x+y)^2-(2x+y)(2x-y)-1]/2y
=[4x＾+4xy+y＾-4x＾+y＾-1]/2y
=[2y＾+4xy＾-1]/2y