ok this is a little bit complicated but doable (well I just did it for your example and it looks very pretty).
First you need to list some regularly spaced (ie 1,2,3 or 5,10,15 or 100,200,300) x values along row 1 (starting in cell b1).
Then list some y values (again regularly spaced...preferably the same values as you used for x) down column A (starting in cell A2).
Next write your formula in cell B2...for your example I used:
=(2*(B$1^2))-($A2^2)-$A2
The dollar signs mean that the formula will always use the value in row 1 or column a.
Autofill the formula (hover the mouse over the bottom right hand corner of B2 until you see a + sign, click and drag) along the whole of row 2, untill you get to the end of your x values, then autofill down until you reach the end of your y values.
Once this is done simply select the cells containing the formula and do a surface chart.
The surface chart uses the cell position to determine the data points x,y co-ordinates and the value in the cell is plotted along the z axis.
I hope this makes some sense.
