Idont get this i just need the answers for 4 and 5

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

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?

Ms.ortiz sells tomatoes wholesale. the function p(x)=-80x^2+320x-10, graphed below, indicates how much profit she makes on a load of tomatoes if she makes on a load of tomatoes if she sells them for 4-x dollars per kilogram. what should ms.ortiz charge per kilogram of tomatoes to make on a load of tomatoes?