We will let the hours of her shift be the values of x and the number of people be the values of y. Now, the gradient of the line is given by (change in y) / (change in x) So let us take 2 values of x and their corresponding values of y. (1 , 70) and (3 , 98) slope = (98 - 70) / (3 - 1) = 14 people per hour The slope-intercept form of a linear equation is: y = mx + c; where m is the slope and c is the y-intercept. c is obtained when x is 0 and this is given to us as 56. Thus, y = 14x + 56
