Need Help with Algebra 2 Question

Question

The per-unit price  (in dollars) of a popular toy when  units (in thousands) are produced is modeled by the function p= 12 - 0.025x. The revenue (in thousands of dollars) is the product of the price per unit and the number of units (in thousands) produced.

So the revenue function is given by r(x) = xp, or rather:

r(x) = x (12 - 0.025x)

According to this function, what is the maximum possible revenue? Type in the number of dollars (without a dollar sign). Be careful, r(x) gives thousands of dollars, not dollars.

Answer 1

r(x) = x(12 - 0.025x)

r(x) = -0.025x² + 12x

Maximum is at x = -b / 2a or x = 24