If f(x) = x + 5, what does f(8) represent?

Question

anonymous · Answer

Is it B?

anonymous · Answer

The value of x when (x + 5) = 8 

 The value of 8f(x) when x = 8 

 The value of f(x) when (x + 5) = 8 

 The value of (x + 5) when x = 8

phi · Answer

If f(x) = x + 5, what does f(8) represent? 

remember  f(x) is the "short name" for the formula  x+5
(it's not very much shorter, but for hairy, complicated formulas it is very helpful)

f(8) is short for:    get the formula  (the x+5),  and everywhere you see x in the formula, put in 8 instead of x

in other words, f(8) means the same thing as  8+5

phi · Answer

can you figure out the answer ?

anonymous · Answer

Is it A?

phi · Answer

f(8) means replace x with 8.  another way to say that is  x=8 in the formula

phi · Answer

the correct answer will have x=8 in it.

anonymous · Answer

Ohh, it's D, right? Thanks soo much! I appreciate it! :)

phi · Answer

yes D.

anonymous · Answer

Thanks soo much! :D <3