Question 943369
Which is it?  Brick wall or a walk, which surrounds the garden?  On ground level the area occupied around the garden has a uniform width of 1.5 meters.  This can be used for the ground level area surrounding the garden.


w width of garden
L length of garden
L=2w;
u, the uniform width of the surrounding area;
u=1.5


{{{(w+2u)(L+2u)-wL=171}}}, account for the surrounding path or area
{{{(w+2u)(2w+2u)-w(2w)=171}}}
{{{2w^2+4uw+2uw+4u^2-2w^2=171}}}, notice inverse to 2w^2...
{{{6uw+4u^2=171}}}
the single variable here is just w.
{{{6uw=171-4u^2}}}
{{{w=(171-4u^2)/(6u)}}}
substitute for u.
{{{w=(171-4(1.5)^2)/(6*1.5)}}}
{{{w=162/9}}}
{{{highlight(w=18)}}}, and according to given, {{{highlight(L=36)}}}.