I too abandoned maths after O levels more than 40 years ago and found the YouTube video enlightening.
I have filled the grid, oriented my letters correctly and identified where I want to put the Xs, but I'm puzzled by brief mention earlier in this thread about a parabola. Am I right in interpreting this as requiring me to draw a parabola connecting the two Xs through the intersection of the X/Y axes? (Or, as in the video, are straight lines acceptable?)
Thanks to anyone who can drag me over the line...