A person has a taco stand. He has found that his daily costs are approximated by C(x)=x²-20 x+340, where C(x) is the cost, in dollars, to sell x units of tacos. Find the number of units of tacos he should sell to minimize his costs. What is the minimum cost?
The person should sell ? units of tacos to minimize the costs. The minimum cost is $ ?.
(Simplify your answers. Type integers or fractions.)