Hey guys! I'm back with a question I am stuck on... thx for the help!

A javelin makes a parabola that follows the equation:

(distance in metres)

height = -1/25 (distance-15)^2 + 10

The first question was easy - find the starting height.

This occurs when d = 0, and you get 1 metre.

The second question; Find the turning point of the javelin = (15,10)

But the last question; what is the horizontal distance covered by the javelin has got me stumpted. It contains a square root sign somewhere in the answer I think, but I need some help.

Thank you!