We notice that the number of pages read is a function of the number of days:
If y is the # of pages read and x the # days, so the equation becomes:
y = m.x + b where m is the rate of reading or the slope and b a constant. How to calculate m? and later b
Note that we can rewrite the given as:
x| 0 | 2 | 5 | 7 |
-|------|-----|-----|------|
y| 57 | 99|162 |204 |
m= (y₂-y₁)/(x₂-x₁) = Rise/Run
m= (204-162)/(7-5) = (162-99)/(5-2) = (99-57)/(2-0) = 21
Then
m = 21 and the function y = 21.x +b
We notice in the table that when x = 0; y = 57, then
57 = 0.x + b that means b = 5 and the final equation is:
y = 21.x + 57