What are 1 of the 4 tips to make a fraction simpler?

What’s the domain of this function? fastttt

Aplane flies around trip to philadelphia it flies to philadelphia at 220 miles per hour and back home with a tailwind at 280 miles per hour if the total trip takes 6.5 hours how many miles does the plane fly round trip

Does anyone know how to solve and graph this: 4 + | a + 2 | < 7the only part i don't get is the "4 +"