according to data from the national safety council, the fatal-accident rate per 100,000 licensed drivers can be approximated by the function

Question

f(x)=.0328x^2 - 3.55x + 115, where x is the age of the driver (16< or equal to x < or equal to 88). at what age is the rate the lowest?

Answer 1

It would occur at at the vertex of this parabola

for f(x) = ax^2 + bx + c, the
x of the vertex is -b/(2a)
so x = 3.55/(2(.0328)) = appr. 54

or, if you are learning how to complete the square ...
f(x)=.0328x^2 - 3.55x + 115
= .0328(x^2 - 108.232 + 2928.53 - 2928.53) + 115
= .0328(x-54.12)^2 + 18.94

vertex is (54.12, 18.94)
etc.

Answer 2

thank you!