化简与求值:求二分之五m-(二分之三m-1)+3(4_m)的值,其中m=—3

问题描述:

化简与求值:求二分之五m-(二分之三m-1)+3(4_m)的值,其中m=—3

5m/2-(3m-1)/2+3(4-m)
=5m/2-3m/2+1/2+12-3m
=m-3m+12.5
=-2m+12.5
m=-3
原式=(-3)×(-2)+12.5=6+12.5=18.5