Hi. Just to add. Charts are nice to start off with, but you may also
want to look at:

In Cells[A1:B2] put
100 , 5
200 , 7

=SLOPE(B1:B2,A1:A2)
=INTERCEPT(B1:B2,A1:A2)

HTH
Dana DeLouis


but I would like to understand how the 3+, etc., are getting
the answer.

<snip