Explanation
Divide the shaded figure into a rectangle with vertices at (2,6), (5,6), (2,2), and (5,2) and a right triangle with vertices at (5,2), (2,2), and (2,0). The rectangle’s height and width are 4 and 3, respectively, and so its area is \(4 \times 3=12\). The triangle has legs of length 3 and 2, and so its area is \(\frac {1}{2} \times 3 \times 2=3\) The sum of the two areas is 12+3 = 15.