3a^2-5a+7-( )=5a^2-11+11 括号里填代数式,让等式成立

分类: 作业答案 • 2021-12-20 04:23:33

问题描述：

答

3a^2-5a+7-( )=5a^2-11+11
3a^2-5a+7-( )=5a^2
3a^2-5a+7-( )-3a^2=5a^2-3a^2
-5a+7-( )=2a^2
-5a+7-(7-5a-2a^2)=2a^2
O(∩_∩)O哈哈~

答

3a^2-5a+7-( )=5a^2-11+11
3a^2-5a+7-( )=5a^2
3a^2-5a+7-( )-3a^2=5a^2-3a^2
-5a+7-( )=2a^2
-5a+7-(7-5a-2a^2)=2a^2