Given the total profit function P(x) = 1.3x-.01x^2-30, let x represent a number of days and find maximum profit achieved and when that profit is made. Then graph the function and mark the vertex
P(x) = 1.3x-.01x^2-30 = -.01x^2 + 1.3x - 30
in more standard notation
you will need the vertex.
The x of the vertex is -b/(2a)
= -1.3/(-.02)
= 65
then P(65) = -.01(65)^2 + 1.3(65) - 30
= 12.25
when x = 65