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
