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

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 :

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

the answer is y < -3 or   y > 3

-3y > 7 + 2

-3 y > 9

y < -3