Chapter CR, Problem 58E

Economic: supply and demand. Demand and supply functions are given by

$p=D\left(x\right)={\left(x-20\right)}^2$ and

$p=S\left(x\right)=x^2+10x+50,$

where p is the price per unit, in dollars, when x units are sold. Find the equilibrium point and the consumer’s surplus.