Question 1152887
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<pre>

Let the width be x meters;  then the length is (x+6) meters.


The perimeter is the sum of four lengths


    P = x + (x+6) + x + (x+6) = 2x + 2*(x+6),   or


    24 = 2x + 2*(x+6).


You may write it in this form


    x + (x+6) = 24/2

    
    x + (x+6) = 12.
</pre>

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I STOP at this point, since the assignment does nor requires to solve the equation.


The person, familiar with the subject, who just solved such problems many times, writes the equation


    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;x + (x+6) = half of the perimeter


without any explanations, assuming that everything is just crystally clear.