A company earns a weekly profit of p dollars by selling x items, according to the equation p (x) = - 0.5x^2+40x-300 how many items does the company have to sell each week to maximize its profit

Legit way is vertex form

easy way is this

x value of vertex in form

f (x) = ax^2+bx+c is - b/2a

the y value is f (x value of vertex)

so

p (x) = - 0.5x^2+40x-300

x value of vertex is - 40 / (2*-0.5) = - 40/-1=40

max profit selling 40 per week

profit would be 500