Question 50513
P(x) = -x^2 + 40x + 825
v(-b/2a,f(x))
-b/2a = -40/(2*-1) = -40/-2 = 20
P(20) = -(20)^2 + 40(20) + 825 = -400 + 800 + 825 = 1,225
v(20,1225)
x-intercepts
0 = -x^2 + 40x + 825
825 = x^2 - 40x
825 + 400 = (x - 20)^2
1225 = (x - 20)^2
+-35 = x - 20
20+-35 = x
(-15,0) and (55,0) are the intercepts
{{{graph(600,600,-16,56,-20,1226,-x^2+40x+825)}}}