To find the answer to an inequality, you treat it just like an equation and try to get the variable by itself. So, to do this we subtract 7 from both sides and we get z < -4
The remaining weight of the empty bottle is 0.5 because each third of the bottle weighs 2.5 pounds and of the remaining juice and the bottle was 3 pounds 2.5 subtracted from 3 is 0.5