Draw From a Point

You can draw a line from a point and a slope without any algebra. Start at the known point and use the slope to find a second point. For the line through (1, -2) with slope 3, move 1 to the right and 3 up from (1, -2) to reach (2, 1). Two points fix the line, so draw the line through (1, -2) and (2, 1).

A negative slope means you move down instead of up for each step to the right. A fractional slope gives you both steps. For slope $\frac{2}{3}$, move 3 to the right and 2 up. The slope is the rise over the run, so the numerator is the vertical step and the denominator is the horizontal step.