如图:
∵丨x-3丨+2丨y+1丨+7(2z+1)^2=0可知x-3=0且y+1=0且2z+1=0，即x=3且y=-1且z=-1/2∴(x+y+z)相反数的倒数=-1/(x+y+z)=-1/(3-1-1/2）=-1/(3/2)=-2/3
