Question 310359
{{{LW=20}}}
{{{L=3+W}}}
 {{{(3+W)W=20}}}
 {{{W^2+3W=20}}}
 {{{W^2+3W-20=0}}} view below.
{{{W=3.2169905660283}}} has to be positive
{{{L=3+W}}}
{{{L=3+3.2169905660283}}}
{{{L=6.2169905660283}}}

*[invoke quadratic "W", 1, 3, -20]