Answer: 16
Step-by-step explanation: f(x) = 3x + 7 means that if we put an x into our function, a 3x + 7 comes out.
So if we want to find f(3), we're putting a 3 into our function which means that a 3(3) + 7 comes out which simplifies to 9 + 7 or 16.
So f(3) = 16 or the value of the function at 3 equals 16.
