The inequality is
.
Rewrite the inequality 
(Divide each side by 6)

(Simplify)
(Multiply each side by negative one and flip the symbol)
(Product of two same signs is positive)
(Divide each side by 6)

(Simplify)
(Multiply each side by negative one and flip the symbol)
(Product of two same signs is positive)
All of the numbers between and including
and 15 are no more than 15 units from 0.
The solution set is 
The graph of the solution set for each inequality on a number line diagram.
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The inequality solution set is
.