问题 解答题
计算:
(1)
3
4
ab+6-3ab-1

(2)7xy+xy3+4+6x-2xy3-5xy-3;
(3)(4x2y-5xy2)+(-3x2y+4xy2);
(4)(5a2+2a-1)-4(3-8a+2a2
答案

(1)原式=-

9
4
ab+5;

(2)原式=2xy-xy3+6x+1;

(3)原式=4x2y-5xy2-3x2y+4xy2=x2y-xy2

(4)原式=5a2+2a-1-12+32a-8a2=-3a2+34a-13.

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