This is impossible to solve.
For an equation or inequality to be solvable, there must be the same number of inequalities as variables. Here, there is an x and there is a y. This means that you need at least two inequalities to solve it.
You can, however, rearrange to get x or y on one side.
This can be done for x:
5x < 10 + 2y
x < 2 + 2/5y
Or it can be done for y:
5x < 10 + 2y
5x - 10 < 2y
2.5x - 5 < y