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化简:(1)3x2-[7x-(4x-3)-2x2](2)(2xy-y)-(-y+yx)(3)5(a2b-3ab2)-2(a2b-7ab2)

题目详情
化简:
(1)3x2-[7x-(4x-3)-2x2]
(2)(2xy-y)-(-y+yx)
(3)5(a2b-3ab2)-2(a2b-7ab2
▼优质解答
答案和解析
(1)原式=3x2-7x+4x-3+2x2
=(3+2)x2+(-7+4)x-3
=5x2-3x-3;
(2)原式=2xy-y+-y-yx
=xy;
(3)原式=5a2b-15ab2-2a2b+14ab2
=(5-2)a2b-(15-14)ab2
=3a2b-ab2