Can someone help me with these 4 questions?

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?

5. (03.02)if g(x) = x2 + 3, find g(4). (2 points)1619811

Find solution of the linear equation y = 2/3x + 1/3