Find the area of the shaded region.
Area = [ (3x + 6)(2x + 4) ] - [ (x - 3)(x - 1) ]
= [ 6x2 + 12x + 12x + 24 ] - [ x2 - x - 3x + 3 ]
= [ 6x2 + 24x + 24 ] - [ x2 - 4x + 3 ]
= 6x2 + 24x + 24 - x2 + 4x - 3
= 5x2 + 28x + 21
