Question

The price C, in dollars per share, of a high-tech stock has fluctuated over a twelve-year period according to the equation C= 14 +12x – x2, where x is in years. The price C, in dollars per share, of a second high-tech stock has shown a steady increase during the same time period according to the relationship C = 2x + 30. For what values are the two stock prices the same?

Answer 1

For this case we have the following equations:
 C = 14 + 12x - x2
 C = 2x + 30
 Equating the equations we have:
 14 + 12x - x2 = 2x + 30
 Rewriting we have:
 -x2 + 10x - 16 = 0
 Solving the polynomial we have:
 x1 = 2
 x2 = 8
 Answer:
 the two stock prices are the same for:
 x1 = 2
 x2 = 8