Help!! I need to know how to do this!?

What’s the domain of this function? fastttt

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?

Asystem of equations has 1 solution.if 4x-y=5 is one of the equations , which could be the other equation ?