How do you know which variable goes with axis when you graph

And employee salary increased by $4500 which represents a 15% raise what is the rate of the increase

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?

When using the linear combination metho e linear combination method to solve a system of linear equations, the four options are: