Question 896576
You might be trying to use x as the width of the pool.


The length of pool is 7 m;
the width of pool is x meters.
The ENDS are the x meter sides, while length are the SIDES of 7 m of the pool.


You should draw a picture to understand the situation clearly.


Area of the Path:  {{{4*2*3+2(3x)+2(2*7)}}}, which is why you need to draw a picture.  The expression is based on what I added for the description about the ENDS and the SIDES.  This path area expression simplifies to {{{6x+52}}}.


Area of the path seems given as 70 square meters.
{{{highlight_green(6x+52=70)}}}
{{{3x+26=35}}}
{{{3x=35-26}}}
{{{highlight(x=3)}}}  meters