function help... Kinda confused. Help please!

[lillybeth]

OK guys... Here is my problem:



The table below represents a function. Which of the following equations could be its function rule?
a). y= -3x
b). y= x
c). y= 3x
d). y= x/-3 How can I find out the function rule, and what is a function rule? Please help! Thanks!

x	y
0	0
1	-3
3	-9
-2	6

 

[MarkFL]

A function basically takes an input (x) and provides an output (y) through an arithmetically defined set of operations. If we have y = 2x, then we know that we take the input, double it, and that is the output. Or if we have \(\displaystyle y=x^2-3\), we know we take the input, square it, then subtract 3, and the result is the output. A function must have just one output for any given input.

Regarding the problem you posted:

We notice that y has the opposite sign of x and its magnitude is 3 times that of x. Put these two observations together to say that y = ?

 

[lillybeth]

A function basically takes an input (x) and provides an output (y) through an arithmetically defined set of operations. If we have y = 2x, then we know that we take the input, double it, and that is the output. Or if we have \(\displaystyle y=x^2-3\), we know we take the input, square it, then subtract 3, and the result is the output. A function must have just one output for any given input.

Regarding the problem you posted:

We notice that y has the opposite sign of x and its magnitude is 3 times that of x. Put these two observations together to say that y = ?

a? y=-3x?

 

[MarkFL]

Yes, that's correct. :cool:

This tells us that whatever x is, we multiply it by -3, and that is y.

 

[lillybeth]

Yes, that's correct. :cool:

This tells us that whatever x is, we multiply it by -3, and that is y.

Great! Thanks for the help, Mark! Guess what? I just got an (A) 95% on a Test that I was studying. (You helped me study) Thanks sooooooo much!!!!!! :grin:

 

[MarkFL]

Well, congratulations, and keep up the good work!

 

[lillybeth]

Well, congratulations, and keep up the good work!