Answer
$x_{com} = -0.45~cm$
Work Step by Step
We can find the x-coordinate of the center off mass:
$x_{com} = \frac{(6L^2)(-L)+(4L^2)(2L)+(8L^2)(-L)+(4L^2)(L)}{6L^2+4L^2+8L^2+4L^2}$
$x_{com} = \frac{(-6L^3)+(8L^3)-(8L^3)+(4L^3)}{22L^2}$
$x_{com} = \frac{-2L^3}{22L^2}$
$x_{com} = -\frac{L}{11}$
$x_{com} = -\frac{5.0~cm}{11}$
$x_{com} = -0.45~cm$
