Math - Solve this inequality algebraically: 3x-15<120?

Change that to an equation and solve it. Then put the solution into the original equation and analyze it.

3x - 15 < 120

3x - 15 = 120

3x = 135

x = 45 <-- This is a point of interest. Now look at a graph of the inequality, at that point. It looks like this: www.wolframalpha.com/input/?i=plot+3x+-+15+%3C+120 The shaded area is your answer.