First, you would plot the point (-2,-5). The next part requires an understanding of what slope is. My teacher told me slope was "rise over run." Basically, the numerator is how much the value of y increases when x increases by the number that's in the denominator. What that means is, when you add 7 to the x value, you add 2 to the y value. You can use this to find another point to graph.
(-2+7,-5+2)
=(5,3)
You can plot this point and draw a line through both points, and you're finished.
Another thing could do is draw a slope triangle. Draw a line (segment) from (-2,-5) for 7 units in the direction of the x-axis. Draw a line (again, a segment, really. We have to be technical xD) from where that segment ends for 2 units in the direction of the y-axis. Plot a point where that ends, and it should be (5,3). Draw a line through (5,3) and (-2,5), and you're done.
Hope I could help you!