计算题(1)n(n+5)-(n-3)(n+2)(2)(x+y+1)(x+y-1)-数学

题目简介

计算题(1)n(n+5)-(n-3)(n+2)(2)(x+y+1)(x+y-1)-数学

题目详情

计算题
(1)n(n+5)-(n-3)(n+2)
(2)(x+y+1)(x+y-1)
题型:解答题难度:中档来源:不详

答案

(1)原式=n2+5n-(n2+2n-3n-6)=n2+5n-n2-2n+3n+6=6n+6;
(2)原式=(x+y)2-1=x2+2xy+y2-1.

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