So here's my question: (by the way, please don't penalise me for putting it in the wrong forum - i didn't see one for graphs!)
The cross section of a hayshed is in the shape of an inverted parabola. It can be
modelled by the equation:
h = 0.3w(8 - w)
where w is the width of the hayshed, and h is the height. Solve w (width).
Please explain how you worked it out?