Find a such that the line $x=$ a divides the region bounded $by$ the graphs $of$ the equations into two regions $of$ equal area. $(Round$ your answer $to$ three decimal places.$)$

$y=x,y=12,x=0$

LarCalc$1214\mathrm{.}3\mathrm{.}055.MI.$

The population density $of$ a city $is$ approximated $by$ the model

$f(x,y)=2,000e^{-0\mathrm{.}01(x^2+y^2)}$ whole number.$$

$243,412$