2x-5y-15=0 I need to know the 3 points I will need to use
I don't know why you need to have three points. Two points are necessary to graph a straight line.
Usually, we can use x-intercept and y-intercept.
x-intercept: y = 0, 2x - 0 - 15 = 0, x = 7.5, (7.5, 0)
y-intercept: x = 0, 0 - 5y - 15 = ...
The solution explains how to find the points necessary to graph a straight line.