Final answer:
To evaluate f(x)-f(4), substitute the value of x into the function f(x) = 4x + 4 and simplify the expression.
Step-by-step explanation:
To evaluate f(x)-f(4), we first substitute the value of x into the function f(x), which is f(x) = 4x + 4. So, f(x)-f(4) = 4x + 4 - (4(4) + 4). Simplifying this expression, we get 4x + 4 - 20. Combining like terms, we have 4x - 16. This is the expression you get after evaluating f(x)-f(4).