m-{n+[4m-3(m+2n)]}-5n其中m=2/3 n=-4

问题描述:

m-{n+[4m-3(m+2n)]}-5n其中m=2/3 n=-4

m-{n+[4m-3(m+2n)]}-5n
=m-{n+[4m-3m-6n]}-5n
=m-{n+[m-6n]}-5n
=m-{n+m-6n}-5n
=m+5n-m-5n
=0