Question 1090190
Original rectangle dimensions, w+2 and w;
Perimeter  {{{p=2(w+2)+2w}}}.


Second rectangle dimensions, 2(w+2) and w-2 for length and width;
Perimeter  {{{2*2(w+2)+2(w-2)=p+12}}}.


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STEPS

{{{p=2w+4+2w}}}
{{{p=4w+4}}}
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{{{4w+8+2w-4=p+12}}}
{{{6w+4=p+12}}}
{{{6w-p=8}}}
{{{6w-(4w+4)=8}}}
{{{6w-4w-4=8}}}
{{{2w-4=8}}}
{{{w-2=4}}}
{{{highlight(w=6)}}}-------width, original rectangle
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{{{w+2=highlight(8)}}}------length, original rectangle