Answer
$x = \frac{20}{3}$
Work Step by Step
In the kite $ABCD$, the measures of $\angle B$ and $\angle D$ are equal.
We can find $x$:
$m\angle B = m\angle D$
$\frac{3x}{2}+2 = \frac{9x}{4} - 3$
$6x+8 = 9x - 12$
$3x = 20$
$x = \frac{20}{3}$