“Find the difference quotient f(x+h)-f(x)/h, where h cannot be equal to 0 , for the function below.

i am stuck, any help would be greatly appreciated!!!

“Find the difference quotient f(x+h)-f(x)/h, where h cannot be equal to 0 , for the function below. f(x)=3x^2+3 Simplify your answer as much as possible”