Math
posted by Larissa .
the international links longdistance phone company charges no monthly fee but charges 18 cents per minute for longdistance calls. the world connections long distance company charges $50 per month plus 10 cents per minute for longdistance calls. compare the world connections longdistance plan to that of international links. under what circumstances is it cheaper to use international links?How to explain my reasoning?

.18x International Links
50 + .10x World Connections
.18x <50 + .10x
solve for x.
The inequality shows where International would be less than World. 
It would be less then the World because of the international and if you add the cost of how much it is the answer shows you that it's less.

Definitely International. Just looking at the problem, you would already agree that International is way cheaper.