Explanation: Slope-intercept form is given by y=mx+b, where m is the slope and b is the y-intercept. The original $50 donated has nothing to do with the profits; if the profits are $0, they will still donate $50. This is the y-intercept, b.
Since they are donating 2/5 of their profits x, this means that the rate of change, or slope, of the line will be 2/5 of a dollar donated per dollar profit; this is m. Plugging these in gives us the equation above.</span>