问题
解答题
计算
(1)3a+4b-5a-b;
(2)-3(1-x)-(1-x-x2)+(1-x+x2-x3)
答案
(1)原式=3a-5a+4b-b=-2a+3b;
(2)原式=-3+3x-1+x+x2+1-x+x2-x3=-x3+x2+x2+3x+x-x-3+1-1=-x3+2x2+3x-3.
计算
(1)3a+4b-5a-b;
(2)-3(1-x)-(1-x-x2)+(1-x+x2-x3)
(1)原式=3a-5a+4b-b=-2a+3b;
(2)原式=-3+3x-1+x+x2+1-x+x2-x3=-x3+x2+x2+3x+x-x-3+1-1=-x3+2x2+3x-3.