3. (p.107 #54) cost analysis: cost equations for manufacturing companies are often
quadratic in nature. if the cost equation for manufacturing inexpensive calculators is
c = x^2 - 10x +31, where is the cost of manufacturing x units per week (both in thousands),
find:
a) the output for a $15 thousand weekly cost.
b) the output for a $6 thousand weekly cost. (1-5)