Basically, it wants you to solve each equation for the variable. If the answer(s) is one of the numbers in the replacement set, then that's a number in the solution set. Otherwise, there's no solution.
For example:
11. z + 10 = 22
z = 12
12 is one of the numbers in the replacement set for z, so the solution set is {12}.
12. 52 = 4z
z = 13
13 is not one of the numbers in the replacement set for z. There is no solution.
