Question 1072654
No other specified information, so assumption is uniform wide walkway around the 50 square meter garden.



Whole yard area,  {{{10*14}}}.


Just the garden area, {{{(10-2*x)(14-2*x)=50}}}, and x is the width around the garden, to be the walkway.


{{{140-48x+4x^2-50=0}}}


{{{4x^2-48x+90=0}}}


{{{highlight_green(2x^2-24x+45=0)}}}
If you really want to solve by completing the square, go ahead.  You start it as  {{{2(x^2-12x+45/2)=0}}}, and the term to add and subtract INSIDE the parentheses is  {{{(12/2)^2=6^2}}}.


You do the rest of this or what you need.


{{{highlight(x=2.33)}}}