The Pennines are the largest mountain range in England, extending from the Peak District in the south to the Cheviot Hills[?] in the north. The name is believed to be derived from the Celticpenno, meaning hill, although no reference to the name can be found before the 18th century.
... left of "=", that will make it a perfect square trinomial of the form x2 + 2xy + y2. Since "2xy" in this case is (b/a)x, we must have y = b/(2a), so we add the square of ...