The Question states Determine f(9/2) for the function f(x)= 3X - 5.
First, a note about typing an upper-case X. The symbol for the input variable is x, as shown in f(x), so use a lower-case x everywhere. Do not interchange symbols x and X, as those are two different symbols in algebra.
Is your son able to show us what he tried (or explain which part he does not understand)?
I'm wondering whether your son understands the concepts of "function" and "function notation".
f(x) is function notation, and so is
f(9/2); these are different ways of writing y, in the following relationship.
y = 3x-5
The letter f in the notation is the name given to the function. In other words, the symbol f does not represent a number. It's handy to assign names to functions, especially when dealing with multiple functions at once.
Symbol x is the input variable, and symbol f(x) is the output variable.
The notation f(9/2) represents the specific output of function f, when the value of the input is 9/2. The value of the input appears inside the parentheses, in function notation. So, x=9/2, in this exercise.
Therefore, the exercise is asking what number comes out of function f when the number 9/2 goes in. Your son needs to substitute the given value for x into the expression 3x - 5, and then he needs to do the resulting arithmetic to come up with the resulting value.
Your son can read more about function notation, by googling the question:
what is function notation? :cool: