Is this graph a function or not a function?

Worth 30 points! in this diagram, both polygons are regular. what is the value, in degrees, of the sum of the measures of angles abc and abd?

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39

Awater tank holds 18000 gallons. how long will it take for the water level to reach 6000 gallons if the water is used at anaverage rate of 450 gallons per day