Question 1063348
w and L the origina width and length
A the original area


{{{system(A=wL,w(L+2)=A+12,(w+3)L=A+21)}}}


That is the system to solve.


The second equation:
{{{wL+2w=A+12}}}
{{{wL+2w=wL+12}}}
{{{2w=12}}}
{{{w=6}}}


The third equation:
{{{wL+3L=A+21}}}
{{{wL+3L=wL+21}}}
{{{3L=21}}}
{{{L=7}}}


Width is 6
Length is 7