(1)简便方法计算:98×102-1002(2)分解因式:a2(x-y)+9(y-x)-数学

题目简介

(1)简便方法计算:98×102-1002(2)分解因式:a2(x-y)+9(y-x)-数学

题目详情

(1)简便方法计算:98×102-1002
(2)分解因式:a2(x-y)+9(y-x)
题型:解答题难度:中档来源:不详

答案

(1)98×102-1002,
=(100-2)(100+2)-1002,
=1002-4-1002,
=4;

(2)a2(x-y)+9(y-x),
=a2(x-y)-9(x-y),
=(x-y)(a2-9),
=(x-y)(a+3)(a-3).

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