How to write a smaller function for given values?

Question

Mathematics

Good afternoon, It
is required to draw up a formula that, on the segment for x from 0 to 9, will give the following values : (x/8)*5*(x-7) Is there a better formula? (less action)

Answer 1

Your graph consists of three straight line segments.
For some reason it seems to me that you need to write it in this form (this is not your formula, just for an example):
Only there will be 3 simple linear functions on three segments.
PS. Your formula does not go through the right points at all.