问题
解答题
计算: (1)
(2)2x(3x2-x+1) (3)(2x+1)(x-3) (4)x(1-x)-x(1+x) (5)(3a+b)(3a-b) (6)(x+
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答案
(1)原式=4×
-3=1-3=-2;1 4
(2)原式=6x3-2x2+2x;
(3)原式=2x2-6x+x-3=2x2-5x-3;
(4)原式=x-x2-(x+x2)=x-x2-x-x2=-2x2;
(5)原式=9a2-b2;
(6)原式=x2+x+
.1 4