x-(7/3-3/4)=1/2解:x=1/2+7/3-3/4 x=6/12+28/12-9/12 x=25/12
X-7/3+3/4=1/2X=7/3-3/4+1/2 =7/3-1/4=(28-3)/12=25/12=2又1/2