See: List of castles, Castles in England, Castles in Scotland, Castles in Northern Ireland
Anglesey
Clwyd
Dyfed
Glamorgan
Gwent
Gwynedd
Powys
South Glamorgan
West Glamorgan
... to <math>x^2+\frac{b}{a}x=-\frac{c}{a}.</math> The equation is now in a form in which we can conveniently complete the square[?]. To "complete th ...