A rectangle length is 6 meters less than 2 times it's width. The perimeter is 426. Solve

2(l+b)=426.

l+b=426/2 =213.

l=2b-6.

2b-6+b=213.

3b=213+6 =219.

b=219/3

=73 msters..

l=2b-6=2*73-6

=146-6

=140 meters.