I know about the basics of boolean conditional formatting, ie. x<y,
xy etc. However, I want to be able to say that for example:

If xy colour yellow, but if xy by more than 10% then colour red, so
that I can see which of my results requires priority. Is there a way
to do this using conditional formatting?

I am using all three conditions as well, I have a traffic light system
in effect, if xy colour green, if x=y colour amber, if x<y colour
green.

thanks.