(A) In the given figure, $ABC$ is a triangle in which $DE \parallel BC$. If $AD = x$, $DB = x - 2, AE = x + 2$ and $EC = x - 1$, then find the value of $x$. BR (B) Diagonals $AC$ and $BD$ of trapezium $ABCD$ with $AB \parallel DC$ intersect each other at point $O$. Show that $\; \frac{OA}{OC} = \; \frac{OB}{OD}$.