Graph the function y = 5x + 4 with the domain x ≤ 0?

The given equation is in the form y=mx+b and that makes it easy to graph because it is a straight line. The slope m=5 is positive which means the line goes up as you go to the right. Every unit to the right, the line goes up five units. The line crosses the y axis at +4 so your first point is (0, 4) and your second point is (1, 9). You can then draw a straight line through those two points and that is your graph.

It looks like this:
www.wolframalpha.com/input/?i=plot+y+%3D+5x+%2B+4,+x%3D-2+to+1