You can
put this solution on YOUR website!I think you may have an error in the equation. Your P(x) equation for profit is a parabola that opens upward, since the coefficient of x^2 is positive. A parabola that opens upward has a MAXIMUM, not a MINIMUM value. Whatever it is, to find the profit if 500 are sold, just substitute the 500 into the value of x in the formula and calculate it.
R^2 at SCC