# Thread: Introduction to functions

1. ## Introduction to functions

I need a help here , I can't understand it

Q- Which relations define y as a function of x?

1) 3x - y^2 + 4=0

2) y= 4x + 2

2. ## Re: Introduction to functions

Originally Posted by moonwoo
I need a help here , I can't understand it
Q- Which relations define y as a function of x?
1) 3x - y^2 + 4=0
2) y= 4x + 2
If $\displaystyle y$ is defined as a function of $\displaystyle x$, then for every $\displaystyle x$ value, there can only be one $\displaystyle y$ value. Try letting $\displaystyle x=0$ for both of those and seeing whether this is true.

3. ## Re: Introduction to functions

Can you solve it to me

4. ## Re: Introduction to functions

No, the only way though this is for you to understand how to solve this problem. First, you need to understand what a relation and a function are and be able to give examples of relations that are functions as well as relations that are not functions. Then you can follow Quacky's advice.

Feel free to ask any questions.