2m-{n+[4m-3(m+2n)]}-5n其中m=2/3 n=-4

问题描述:

2m-{n+[4m-3(m+2n)]}-5n其中m=2/3 n=-4

2m-{n+[4m-3(m+2n)]}-5n
=2m-{n+[4m-3m-6n]}-5n
=2m-{n+[m-6n]}-5n
=2m-{m-5n}-5n
=2m-m+5n-5n
=m
=2/3