math
posted by Mary18 on .
Please explain in detail so I can understand how to do it:
A football player punts a ball. The path of the ball can be modeled by the equation y = 0.004x^2 + x +2.5, where x is the horizontal distance, in feet, the ball travels and y is the height in feet, of the ball. How far from the football player will the ball land? Round to the nearest tenth of a foot.

Here is a graph showing the path of the ball
http://www.wolframalpha.com/input/?i=0%3D+0.004x%5E2+%2B+x+%2B2.5
So the xintercept would be the distance covered
so 0.004x^2 + x +2.5 = 0
use the quadratice equation were
a = .004, b = 1, and c = 2.5
x = (1 ± √1.04)/.008
= appr. 252.8 or a negative