SOLUTION: The path of a platform diver can be described by the equation y=-2x^2+15x+6, where x is the horizontal distance in meters of the diver from the edge of the platform and y is the he

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: The path of a platform diver can be described by the equation y=-2x^2+15x+6, where x is the horizontal distance in meters of the diver from the edge of the platform and y is the he      Log On


   

Question 27151: The path of a platform diver can be described by the equation y=-2x^2+15x+6, where x is the horizontal distance in meters of the diver from the edge of the platform and y is the height of the diver in meters above the surface of the water.In horizontal distance, about how far in front of the platform will the diver enter the water?
I cant seem to break this down and get an answer?
Thanks SOOOOO Much for any help!
Answer by bmauger(101) About Me  (Show Source):
You can put this solution on YOUR website!
When your diver hits the pool will be when y (elevation) equals 0. Of course since this is a quadratic equation it will have two answers, but one of them will be negative and make no sense.
You're right, it doesn't factor. So you can use the quadratic formula to solve it:
%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29
%28-15%2B-sqrt%2815%5E2-4%28-2%29%286%29%29%29%2F%282%2A%28-2%29%29
%28-15%2B-sqrt%28273%29%29%2F%28-4%29
%2815%2B-16.523%29%2F4
31.523%2F4-1.523%2F4
7.88-0.381
So the only possible answer is 7.88 (AKA %2815%2Bsqrt%28273%29%29%2F4)
Graphically the dive looks like:
graph%28+230%2C+200%2C+-1%2C10%2C+-3%2C35%2C+%28-2x%5E2%2B15x%2B6%29%29