Question 1005258
2w+2L=268, and the description then indicates  w+12 and L+12 to be the new dimensions.


{{{w+12=(3/8)(L+12)}}}
{{{8w+96=3(L+12)}}}
{{{8w+96=3L+36}}}
{{{8w-3L=36-96}}}
{{{8w-3L=-60}}}
{{{highlight_green(3L-8w=60)}}}


Use the perimeter information.
{{{w+L=134}}}
{{{L=134-w}}}
-
Substitute
{{{3(134-w)-8w=60}}}
{{{402-3w-8w=60}}}
{{{-11w=60-402}}}
{{{11w=402-60}}}
{{{11w=342}}}
{{{highlight(w=31&1/11)}}}


{{{L=134-31&1/11}}}
{{{highlight(L=102&10/11)}}}