用2种方法计算:(n+5)^2-(n-5)^2

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/04 05:42:27
用2种方法计算:(n+5)^2-(n-5)^2

用2种方法计算:(n+5)^2-(n-5)^2
用2种方法计算:(n+5)^2-(n-5)^2

用2种方法计算:(n+5)^2-(n-5)^2
:(n+5)^2-(n-5)^2
=(n+5+n-5)(n+5-n+5)
=2n*10
=20n;
:(n+5)^2-(n-5)^2
=n²+25+10n-n²-25+10n
=20n;