Given: $($x is number of items$)$

Demand function: d$($x$)=5000\mathrm{.}3$xd$($x$)=500-0\mathrm{.}3$x

Supply function: s$($x$)=0\mathrm{.}5$xs$($x$)=0\mathrm{.}5$x

Find the equilibrium quantity: $$

Find the consumers surplus at the equilibrium quantity: