Answer:
3a^2 - 7a - 6
Step-by-step explanation:
Find the average length of the light gray shaded figure. It is:
4a + 5 + 2a - 1 6a + 4
--------------------- = --------------- = 3a + 2
2 2
Now multiply this average length, 3a + 2, by the width, a - 3:
Area of light gray figure is (3a + 2)(a - 3) = 3a^2 - 7a - 6
