4z+2(z-4)=3z+11 perform indicated multiplication on left side
4z+2z-8=3z+11 combine like terms on left side
6z/-8=3z+11 add 8 to both sides
6z=3z+19 subtract 3z from both sides
3z=19 divide both sides by 3
z=19/3
z=6 1/3
So there is only one solution when z=6 1/3