The slope is a rate, so the slope is $2/glass. The y-intercept is a constant, so the y-intercept is –10. This makes the equation y=2x-10, where x represents the number of glasses sold and y represents the amount of profit. I would label the horizontal axis “Number of glasses sold” and the vertical axis “Profit.” This is because Molly uses the number of glasses sold to calculate her profit. The number of glasses sold is the independent variable, and the profit is the dependant variable.