Posted by
**elizabeth** on
.

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.