The cost y (in dollars) to provide food for guests at a dinner party is proportional to the number x of guests attending the party. it costs $30 to provide food for 4 guests.

!! 10 ! a westbound jet leaves central airport traveling 635 miles per hour. at the same time, an eastbound plane departs at 325 miles per hour. in how many hours will the planes be 1900 miles apart?

If a || b and e || f , what if the value of y ?

How do you determine if an ordered pair is a solution to a given equation?