9 hours and 35 min.
11:50 - 2:15

The numbers are 3, 7, and 11.
Interval Notation:
(−∞,∞)
Set-Builder Notation:
{x|x∈R}
All three of these angles will add up to 180.
Set up an equation so all three will add to 180:

Combine like terms:

Divide both sides by 12:

x will equal
15.