If x+3y=7 and x-3y=1 what's y

The graph shows the rate at which paint is used to paint a wall.enter values to complete each statement below based on the graph.when 1 gallon of paint has been used, ( # ) square feet of the wall will be painted.the unit rate is ( # )square feet per gallon.

What is the least common multiple of 16 and 3?

Can someone me out here and the tell me the greatest common factor