fojxl lives in Honington, England. He reads a lot of science fiction and is going to avoid getting too near any of the weightier topics that make up the Wikipedia...
... the common denominator is 4a2. We get
<math>\left(x+\frac{b}{2a}\right)^2=\frac{-4ac+b^2}{4a^2}=\frac{b^2-4ac}{4a^2}.</math>
Taking square roots ...