What is the output value of a function? Is it the f(x), or the second part of the function equation?

I am confused?

Also, can some1 help me on this question?

A function is given below.

f(x)= x + 2

Which is a true statement about this function?

A. The output value of the function is 1 when the input value is 3.

B. The output value of the function is x when the input value is 2.

C. The output value of the function is 2 when the input value is x.

D. The output value of the function is 3 when the input value is 1.

This is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 5 terms.