题目内容
【题目】计算:
(1)(2x2y)3÷(x3y2); (2)(a+2)(a-3)+(a+3)(a-3);
(3)(x-y+5)(x-y-5);
(4)899×901+1.(用乘法公式进行计算)
【答案】(1) 8x3y;(2) 2a2-a-15.(3) x2-2xy+y2-25;(4) 810 000;
【解析】试题解析:(1)解:原式=8x6y3÷(x3y2)
=8x3y.
(2)解:原式=a2-a-6+a2-9
=2a2-a-15.
(3)(x-y+5)(x-y-5);
解:原式=[(x-y)+5][(x-y)-5]
=(x-y)2-52
=x2-2xy+y2-25.
(4)解:原式=(900-1)×(900+1)+1=9002-12+1=810 000.
故答案为(1) 8x3y;(2) 2a2-a-15.(3) x2-2xy+y2-25;(4) 810 000.
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