题目内容
化简:(1)(2x+a)2-(2x-a)2
(2)[(2x2)3-6x3(x3+2x2)]÷(-2x2)
(3)(x-2)(x+2)-(x+1)(x-3)
(2)[(2x2)3-6x3(x3+2x2)]÷(-2x2)
(3)(x-2)(x+2)-(x+1)(x-3)
(1)原式=[(2x+a)+(2x-a)][(2x+a)-(2x-a)]
=(2x+a+2x-a)(2x+a-2x+a)
=4x•2a
=8ax;
(2)原式=(8x6-6x6-12x5)÷(-2x2)
=2(x6-6x5)÷(-2x2)
=-x4+6x3
=6x3-x4;
(3)原式=x2-4-(x2-2x-3)
=x2-4-x2+2x+3
=2x-1.
=(2x+a+2x-a)(2x+a-2x+a)
=4x•2a
=8ax;
(2)原式=(8x6-6x6-12x5)÷(-2x2)
=2(x6-6x5)÷(-2x2)
=-x4+6x3
=6x3-x4;
(3)原式=x2-4-(x2-2x-3)
=x2-4-x2+2x+3
=2x-1.
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