Is 3,9 a solution to the equation y=3x

Sara can take no more than 22 pounds of luggage on a trip. her suitcase weighs 112 ounces. how many more pounds can she pack without going over the limit?

Arestaurant chef made 1 1/2 jars of pasta sauce. each serving of pasta requires 1/2 of a jar of sauce. how many servings of pasta will the chef be bale to prepare using the sauce?

For f(x) = 3x+1 and g(x) = x2 - 6, find (g/f)(x)