Rectangle ABCD has vertices C and d on the x-axis and vertices A and B on part of the parabola y = 9 - x^2 that is above the x-axis.

Question

a.) Find the coordinates of A, B, C, and D in terms of x.
b.) Determine the Area of the rectangle as a function of x.
c.) What is the domain for the area function? Hint: Area cannot be negative

well I'm completley lost here on how to do this
also for c. technically speaking can't area be negative area is a tensor a magnitude with more then one direciton no? So an area can be negative it would just be in the set of complex numbers no?