Sum of 5 times z and 4 divided by two is 7.
you can't factorize it in rational numbers
Sorry, don't have time to do them right now but I know who does!
http://www.wolframalpha.com/widgets/view.jsp?id=ae438682ce61743f90d4693c497621b7
Just plug in 2 at a time.
• 18 baseball cards
• 12 football cards
The only relationships shown in the table is in week 1, where the ratio of baseball to football cards is baseball : football = 9:6
:)