Question

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

Answer 1

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.