Edmentum inverse functions mastery test

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

Which is the focus of a parabola with equation y2=4x