An economist uses the model P (x) = minus−0.05xsuperscript3end of superscript, + 3.25xsuperscript2end of superscript, - 10x + 20 to estimate the price of a stock over the next 8 years.When does the stock reach at least $34.24?Enter a whole number of years. (Hint: An answer of 6.23 years refers to being in the seventh year.)

-.05x^3 + 3.25x^2 - 10x + 20 = 34.24

Easiest to solve this by a graph :

In the 5th year....