Question 849327
Write everything you know about the original square and the increased square.  Look for the equations or equation to solve for the unknown variable or variables.


ORIGINAL SQUARE
w=side length
p= perimeter,
{{{4w=p}}}


NEW BIG SQUARE
Now, side length made into w+2.
P = perimeter of new square.
{{{4(w+2)=P}}}.
{{{P=-3+5w}}}.
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Before YOU try to go any further, can you see how the last two equations involving P were obtained?  Recheck my variable assignments; and recheck the problem description.  




Continuing-----
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Those two formulas for capital P are equal and once equated as an equation, the only unknown variable is w.
{{{4w+4*2=5w-3}}}
{{{4w+8=5w-3}}}
{{{8+3=5w-4w}}}
{{{highlight(highlight(highlight(w=11)))}}}