问题 解答题
计算:
(1)5x+4x;
(2)-5x2+
1
5
x2

(3)6x-10x2+12x2-5x;
(4)x3-x2+4-2x3-2+3x2
答案

(1)原式=9x;

(2)原式=-

24
5
x2

(3)原式=6x-5x-10x2+12x2=x+2x2

(4)原式=x3-2x3+3x2-x2+4-2=-x3+2x2+2.

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