How to solve this problem? |n+7|=5

Set it equal to 5 and -5 because absolute value is just the distance from zero no matter which way. 

The "maple leaf rag" (copyright registered on september 18, 1899)[1] is an early ragtime musical composition for piano composed by scott joplin. it was one of joplin's early works, and became the model for ragtime compositions by subsequent composers. it is one of the most famous of all ragtime pieces.[2] as a result joplin was called the "king of ragtime". the piece gave joplin a steady if unspectacular income for the rest of his life.

Sumo is the answer to the question