From the figure, we can get the system of equations x+3y= 14.

x+y-2y=6

X=8 can be obtained by solving the equation.

y=2

The width of this big rectangle is 2y+6= 10.

The area of a large rectangle is 14× 10= 140.

The area of a small rectangle is 8×2= 16.

∴ Shadow area is 140- 16×6=44(cm? )