SOLUTION: A soccer ball is kicked. Its height (in feet) in the air is modeled by h(x) = -0.0498x^2 + 0.7538x, where x is the horizontal distance (in feet) the ball has traveled since being k

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A soccer ball is kicked. Its height (in feet) in the air is modeled by h(x) = -0.0498x^2 + 0.7538x, where x is the horizontal distance (in feet) the ball has traveled since being k      Log On


   

Question 1056879: A soccer ball is kicked. Its height (in feet) in the air is modeled by h(x) = -0.0498x^2 + 0.7538x, where x is the horizontal distance (in feet) the ball has traveled since being kicked. How far does the ball travel before hitting the ground?
What formula should I use?
Is it: -b/2a or - (b^2 - 4ac)/4a or -b + - square root of b^2 - 4ac/ 2a and why?
Thanks a lot

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
h(x) = -0.0498x^2 + 0.7538x
Set it equal to 0.
factor out a -x(0.0498x-0.7538x=0
0.0498x=0.7538
x=15.13 feet
You can use x=(1/2a)(-b+/- sqrt (b^2-4ac)), but in this instance the factoring is easier.
graph%28300%2C300%2C-1%2C17%2C-10%2C10%2C+-0.0498x%5E2%2B0.7538x%29
-b/2a gives the x value of the vertex, useful when you want to know the maximum height of the ball.