If you get a function like f(2), you have to know that the 2 in the brackets/parentheses pretty much replaces the “x” in the equation. Think about it:
If we have f(x) and f(2), that must mean x=2
So we insert the value of x into the function and we get:
f(2)= 2*2+1=4+1=5
So 5 is the answer
