m减2的绝对值加n加二分之一的和的二次方等于0
∵ (|m-2|+n+1/2)² =0
∴ |m-2|=0 n+1/2=0
∴m=2 n= -1/2
则:mn加n分之m
=2×(-1/2)+2/(-1/2)
=-1+(-4)
=-5