<span>"Which represents the solution set of the inequality 5x" is not clear.
The inequation is 5<x, 2x-4>0, or x+y<3.......</span>

Cross-Multiply:

Divide by 3 on both sides:

Divide by x on both sides:
Let's start with what we know:

And we are trying to put it into this form:

Here is what it would look like:

You can check you work by using the FOIL method (first, outer, inner, last)
The answer is -4. Hope this helps!!