计算.(1)a(2a-b)+(2b-1)(a+1)-2a2;(2)(-2x2y)3•(3xy2)2;(3)1002-992+982-972+962-952+…+
题型:解答题难度:一般来源:不详
计算. (1)a(2a-b)+(2b-1)(a+1)-2a2; (2)(-2x2y)3•(3xy2)2; (3)1002-992+982-972+962-952+…+22-12. |
答案
(1)a(2a-b)+(2b-1)(a+1)-2a2; =2a2-ab+2ab+2b-a-1-2a2 =ab+2b-a-1;
(2)(-2x2y)3•(3xy2)2; =-8x6y3×9x2y4 =-72x8y7;
(3)1002-992+982-972+962-952+…+22-12. =(100+99)(100-99)+(98+97)(98-97)+…+(2+1)(2-1) =199×1+195×1+…+3×1 =199+195+…+3 =(199+3)×100÷2 =5050. |
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