In Problems, sketch the region bounded by the graphs of the given equations, show a typical slice,

Question:

In Problems, sketch the region bounded by the graphs of the given equations, show a typical slice, approximate its area, set up an integral, and calculate the area of the region. Make an estimate of the area to confirm your answer.
(a) y = 3 - 1/3x2, y = 0, between x = 0 and x = 3
(b) y = 5x - x2, y = 0, between x = 1 and x = 3
(c) y = (x-4) (x+2), y = 0, between x = 0 and x = 3