math
posted by Punkie .
Could someone please help me with this problem I don't know how to solve it and I am terrible at word problems.
The amount of background noise is important to television news reporters. One station developed the formula N = t^2 + 12t + 54 showing the noise level in decibels (N) as it relates to the time after the speaker stops talking in seconds (t). How many seconds after the speaker stops will the noise level be the greatest? Write and tell how you decided.

N is parabolic; the maximum occurs at the vertex. The vertex has an xvalue that is halfway between xintercepts, which can also be found by a graphing utility or by calculus.