Start at the origin, it's where the x and y axis intersect. Then go up 12 units on the y-axis, because the y-intercept is equal to 12. Then use the slope of -6 to plot the next point on the graph. This means from the y-intercept go down 6 units and then run 1 unit to the right, or you could go up 6 units and then 1 unit to the left. The equation of the line is in slope-intercept form y=mx+b. The variable m represents the slope and the letter b represents the y-intercept.