I have these questions for an assignment we're meant to do using Microsoft Excel.

Set up a table to find the negative root of x2 - 4x - 8 = 0

Find another re-arrangement of the equation x2 - 4x - 8 = 0 to find the positive root by iteration.

I have no idea what negative/positive roots are (the teacher never taught it) , and no clue how to finish this. If anyone could help I'd be extremely grateful.