Question

Explain to how to solve for f(3)

@ganeshie8 @phi @jdoe0001 @whpalmer4
@KingGeorge

Answer 1

f(3) is short for find the formula they give for f(x)
replace the x with a 3 in the formula
do the arithmetic in the formula and find a number.
can you do that ?

Answer 2

I have helped another person with this problem, and thus know that you have omitted some of the problem statement. Please make sure to share EVERYTHING about each problem when you post a question to OpenStudy;

Answer 3

Note that you are NOT given f(x); instead, you are given an equation and from it you have to create y our own function f(x).

Answer 4

@phi for some reason openstudy seemed to be down but can you elabroate on this?

Answer 5

@jigglypuff314

Answer 6

f(3) means to plug in 3 for x

for example if f(x) = x+5
then f(3) = 3+5 = 8

Answer 7

you need a formula for f(x)

For example, f(x) = 2x + 2

f(3) would mean: replace x with 3: 2*3 + 2 (by the way 2x is short for 2 times x)
now simplify. remember order of operations. first do the multiply 2*3=6 . then do the add 6+2 = 8
f(3)= 8

Answer 8

Did they give you a formula for f(x) ?

Answer 9

no i had to write one and cant think of an equation

Answer 10

write down the equation for a line.

if you really want simple, write y= x

Answer 11

or f(x) = x

Answer 12

@phi: No, they did not provide a formula for f(x). A significant amount of info is missing from this problem statement. What was provided was an EQUATION in x only (no y, no f(x) ). I hope @aleisha96 will double check on the remaining info in this problem statement and provide it to us.

Answer 13

@mathmale a function was not provided for me i just explained that there is no missing info

Answer 14

I'm sorry to hear that. I recognize this problem from having worked with another student whose first goal was to find f(3). Looks like there's not much more I can say or do to help if you have no further info.

Answer 15

@jigglypuff314 can you help me please?

Answer 16

both I and phi have provided examples for your f(3)
what more would you like? :)

Answer 17

i need help forming an equation that will fit into solving for f(3)

Answer 18

alright :)
so to do that it would be f(x) = (something)
you get to pick what that (something) is :)
it can be like x+3 or 2x+5 or even just x

Answer 19

@aleisha96 :

I'd like very much to see you able to finish solving this problem.

May I suggest that you plan to ask your teacher, tomorrow, whether there is not more info, and in the meantime move on to solving other problems?

Without f(x), you're wandering in the dark (if you'll forgive my putting it that way).

Answer 20

Or, there could be a ridiculously easy verbal response:

"Given the function f(x), evaluate f(3) by replacing every instance of x with 3." That's it.

Examples: If f(x) = 5x, f(3) = 5 (3) = 15.
If f(x) = sin x, f(3) = sin 3 (assuming that x is an angle and is measured in radians).

Answer 21

jigglypuff and phi have suggested the same thing: invent f(x) and then substitute 3 for x. Done.

Answer 22

Does you problem have anything to do with martians?

Answer 23

Yes, particularly to do with one Martian named Harry and the other one Richard.