Question 688769
Set-Up
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X = length
Y = width
Equation 1: {{{28 = 2X + 2Y}}}
Equation 2: {{{X = Y + 4}}}

Solution:
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Plug (Y + 4) into equation 1 for X
Equation 1: {{{28 = 2X + 2Y}}}
{{{28 = 2(Y + 4) + 2Y}}} Simplify
{{{28 = 2Y + 8 + 2Y}}} Combine like terms
{{{28 = 4Y + 8}}} Subtract 8 from both sides
{{{20 = 4y}}} Divide both sides by 4
{{{highlight(5 = Y)}}}
Now plug 5 into equation 2 for Y
Equation 2: {{{X = Y + 4}}}
{{{highlight(X = 9)}}}