In interval notation what is 20-|7x+1|>=6

20-|7x+1| >= 6

|7x+1| <= 14
|x + 1/7| <= 2
x∊[-15/7,13/7]

http://www.wolframalpha.com/input/?i=solve+20-|7x%2B1|+%3E%3D+6