How do you solve $abs(5n-1) = 7$ ?

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Answer 1 · 2015-09-27T22:39:40

See the explanation.

$|5n-1|=5n-1, 5n-1>=0 <=> 5n>=1 <=> n>=1/5$
$|5n-1|=-5n+1, 5n-1<0 <=> 5n<1 <=> n<1/5$

We need to solve 2 equations:
$5n-1=7 <=> 5n=8 <=> n=8/5>1/5$ is a solution
$-5n+1=7 <=> -5n=6 <=> n=-6/5<1/5$ is a solution

How do you solve abs(5n-1) = 7abs(5n-1) = 7?