find the difference quotient for f(x)= 3x-7

By difference quotient, I suppose you mean:

\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}?

\lim_{h\to 0}\frac{[3(x+h)-7]-(3x-7)}{h}

Simplify, take the limit, and you should get the derivative of 3x-7 (which is 3).

3

Thank You Very Much