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?
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
