Answer: 16
Explanation: f(x) = 2x - 4 means that if we put an x into our function, a 2x - 4 comes out.
So if we want to find f(5), we're putting a 5 into our function which means that a 2(5) - 4 comes out which simplifies to 10 - 4 or 6.
So f(5) = 6 or the value of the function at 5 equals 6.