Question

Mr. Lewis fixes electronic equipment. He uses the function f(x) = 80x + 250 to determine his total charge, f(x), in dollars, where x is the number of hours he works. Which statement represents the rate of change of the function?

Answer 1

Given:

Total charge, f(x), in dollars, for x number of hours is

`f(x)=80x+250`

To find:

The correct statement for the rate of change of the function.

Solution:

Slope intercept form of a linear function is

`y=mx+b` ...(i)

where, m is slope and b is y-intercept.

We have,

`f(x)=80x+250` ...(ii)

On comparing (i) and (ii), we get

`m=80, b=250`

Therefore, the slope or rate of change of the function is 80 and it represents that per hour changes are 80.