How do I do this this is due tomorrow please I need help

Write two subtraction equations that are equivalent to 5 + 12 = 17.

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?

Acircle has a radius of 5/6 units and is centered at (3.6, 7.8) write the equation of this circle