23-a-｛10a-[(5a-15)-(4-6a)]｝

分类: 作业答案 • 2021-12-19 16:49:52

问题描述：

答

原式=23-a-{10a-[5a-15-4 6a]}
=23-a-{10a-[11a-19]}
=23-a-{10a-11a 19}
=23-a-10a 11a-19
=23-19
=4