Simplify the Difference Quotient for the Linear Function $f(x)$ , and Use It to Identify the Rate of Change

Multiple Choice

Simplify the difference quotient for the linear function $f(x)$ , and use it to identify the rate of change of the function.
- $f(x) =75 x-675$

A) -675
B) 75
C) 675
D) -75