请帮我把这几道多项式题做一下！

已知多项式3-2x^+3x+3x^-5x-x^-7

(1)当x等于负二分之1时，求这个多项式的值；（2）当x为何值时，这个多项式的值为2？（这两道题都要一步一算）不然不采纳

3-2x^+3x+3x^-5x-x^-7=3-7-2x^+3x^-x^+3x-5x=-4-2x

(1) 降x=-1/2带入上式 即 -4-2×（-1/2）=-3

(2) -4-2x =2 求得 x=-3

1.将x=-0.5代入式子

=3-2x(-0.5^2)+3x(-0.5)+3x(0.5^2)-5x(-0.5)-(-0.5^2)-7

=3-2x0.25-1.5+3x0.25+2.5-0.25-7

=3-0.5-1.5+0.75+2.5-0.25-7

=2.5-1.5+0.75+2.5-0.25-7

=1+0.75+2.5-0.25-7

=1.75+2.5-0.25-7

=4.25-0.25-7

=4-7

=-3

2.3-2x^2+3x+3x^2-5x-x^2-7=2

-2x^2+3x^2-x^2+3x-5x+3-7-2=0

x^2-x^2+3x-5x+3-7-2=0

3x-5x+3-7-2=0

-2x=7+2-3

-2x=6

x=-3