Which is the solution set of the inequality 15y-9 <36?

15y - 9 < 36

15y < 36 + 9

15y < 45

y < 45/15

y < 3

So y could be, 2, 1.5, 1, 0, - 1, - 2, - 3, - 3.8, ...

So the set can be written as:

[-∞, 3)

That is to say all numbers between minus infinity and 3. 3 is not included.