Question 1184140
Original length, L
Original width, L/3


The "if" part of description
{{{(L-3)(L/3+2)=12}}}


Maybe a little bit easier to multiply both sides by 3.
{{{(L-3)*3(L/3+2)=3*12}}}

{{{(L-3)(L+6)=36}}}-------------------Factors of 36 which can work,  3 & 12.



L-3=3, and L+6=12;
Solve either or both for L.

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