Question

For the function f(x) = –x + 21, what is the difference quotient?

Answer 1

Answer:

The difference quotient is the quotient of the difference of the function values, f(x + h) - f(x), and the difference of the input values, (x + h) - x.

Given the function f(x) = -x + 21.

The different quotient will be : $\frac{f(x+h)-f(x)}{(x+h)-x} =\frac{f(x+h)-f(x)}{h} = \frac{(-(x+h)+21)-(-x+21) }{h} = \frac{-x-h+21+x-21}{h} = \frac{-h}{h} = -1$

We see that given the function f(x) = -x+21 and two input values of x and x + h, the difference quotient is -1.