You received a $100 gift certificate to a clothing store. the store sells t-shirts (x) for $15 and dress shirts (y) for $22. you want to spend no more than the amount of the gift certificate. you want to leave at most $10 of the gift certificate unspent. you need at least one dress shirt.

You still want at most 

(15x) + (22y) ≤ 100(-z)           (equation used)

0 ≤ z ≤ 10                              (amount you want to leave unspent)

y ≥ 1                                     (amount of dress shirt you need)

This is your system of equation, in which the numbers must fulfill both equations

hope this helps