Expert: Steve Holleran - 9/13/2007

Question
Okay I have no idea about function rules.
I need to write one for this input-output table.
x- 0  1 2 3 4 5 6 7 8 9 10
y- 10 9 8 7 6 5 4 3 2 1 0

I don't know how to solve this.

Answer
Hi Amanda,

Okay, do you notice that the x's are getting bigger by 1 and the y's are getting smaller by 1 each time?

Since the y's are getting smaller, this suggests that there is some subtraction going on.

Notice also, when x = 0, y = 10; then when x = 1, y = 9.

This means that something is taken away from the 10.

                y = 10 - something

Notice now that if we subtract each x from 10, we get each y.  This means we can write:

               y = 10 - x  and it works for each x value in the table.

I hope this helps you out
Steve Holleran