Question 1073236
w width
L length
A area
{{{system(w=L+10,A=231,wL=A)}}}


{{{highlight_green((L+10)*L=231)}}}


{{{L^2+10L-231=0}}}

{{{(L-11)(L+21)=0}}}

{{{highlight(L=11)}}} and {{{highlight(w=21)}}}.