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

Demand function: d$($x$)=396\mathrm{.}90\mathrm{.}3$x$2$d$($x$)=396\mathrm{.}9-0\mathrm{.}3$x$2$

Supply function: s$($x$)=0\mathrm{.}6$x$2$s$($x$)=0\mathrm{.}6$x$2$

Find the equilibrium quantity: $$

Find the consumers surplus at the equilibrium quantity: