Answer
$\frac{1}{x+2}$
Work Step by Step
The area of the triangle is: $\frac{1}{2}a\times h=\frac{1}{2}x\times2=x$
The area of the rectangle is: $l\times w=x(x+2)$
Therefore, percent shaded is:
$\frac{S_{triangle}}{S_{rectangle}}=\frac{x}{x(x+2)}=\frac{1}{x+2}$
