## College Algebra 7th Edition

$x=9$ feet.
The area of the empty space in addition to the shaded area is $10(x+6)=10x+60$. The area of the empty space alone is $6(10-x)=60-6x$ Therefore, the area of the shaded area is $(10x+60)-(60-6x)$. This also equals $144$ square feet, so $16x=144$, and $x=\frac{144}{16}=9$ feet.