Answer: x^2+29x+39
You would first have to set up an equation, which would be ((2x+9)⋅(x+6))-((x-5)⋅(x-3)) to find the area of both rectangles.
Then you can simplify it, which gives us 2x^2+21x+54-(x^2-8x+15)
Then simplify it even more which gives us 2x^2+21x+54-x^2+8x-15
Then we can get our answer: x^2+29x+39
Hope that helps :)