Ims struggling with this question help???

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?

Write an expression that has three terms and simplifies to 4x - 7. identify the coefficient(s) and constant(s) in your expression

What set does not contain -3 the set of all real numbers the set of all integers the set of all whole numbers the set of all rational numbers