Number of Miles 611
Intersections with other Interstates
Spur Routes
Notes When I-77 and I-81 merge in Virginia, you are going both north and south on a wrong-way multiplex.
... both sides yields <math>x+\frac{b}{2a}=\frac{\pm\sqrt{b^2-4ac}}{2a}.</math> Subtracting b/(2a) from both sides, w ...