posted by elizabeth .
My kids are stuck on this they've no idea what to do and I can't help them out either!
Darren throws a stone from the top of a vertical cliff into the sea below.
The trajectory of the stone can be modelled by the quadratic equation
y = -(x^2/3)+2x+24
where y represents the height in metres of the stone above sea level, and x is the horizontal distance of the stone from the bottom of the cliff
measured in metres.