Impact of French society: towns such as Chartres are becoming "TGV commuter belt"; Brussels - Paris in 90 minutes has increased commuting between the two capitals; likewise Paris - Marseille time greatly reduced recently
Impact of the building of the lines: many years of wrangles over the Lyon-Marseille line
... to both sides, getting
<math>x^2+\frac{b}{a}x+\frac{b^2}{4a^2}=-\frac{c}{a}+\frac{b^2}{4a^2}.</math>
The left side is now a perfect square; it is the ...