Evaluate the function for x = - 8.

f (x) = - 2x - 12

a. 28

b. - 40

c. - 28

d. 4

To evaluate a function, simply replace (substitute) the function's variable with the indicated number or expression. A function is represented by f (x) = 2x + 5. Find f (3). To find f (3), replace the x - value with 3. thats how you evaluate a function but i dont know the answer i just gave you an example.