How did Charlemagne become a rival to the Byzatine
emperors and the Abbasid caliphs?

He proclaimed himself as the Holy Roman Emperor and spread his territory in all directions. While doing that he enter into quarrel with these two countries.

Explanation:

Charlemagne proclaimed himself as an emperor in 800. Until then only rulers of Byzantine Empire had that title in Europe. They didn't accept this, especially as Charlemagne proclaimed himself as the successor of  Roman emperors.

Abbasid caliphs fought with Charlemagne as he tried to take their territory in Spain.

the cost of college has risen faster than inflation for many years.

the high price of student services and administration are two reasons for the rapid increase in cost.

answer: the ocean

explanation: if you map out 30 n and 40 n latitude, you will get the ocean