Posted by Angie on .
Is the relationship between y and x linear?
x y
0 2
4 5
8 8
12 11
i don't think it's linear.

Math 
Count Iblis,
Why not?

Math 
Angie,
because i can't write an equation for y.

Math 
Count Iblis,
If you assume that Y is linear, then you can write down an equation. Then you take the first two points to completely fix the undetermined constants in that equation.
Then you have arrived at the following conclusion:
Assuming that the relation is linear, y is given in terms of x as follows...
Then you check if the other points are consistent with this equation. If the relation is linear, they must be consistent with that equation. So, if it is not, then the relation cannot be linear. 
Math 
Angie,
I don't think y is linear. If it is, what's the equation? y=.....