Question 1170286
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<pre>

Let x be the length of either of the two congruent sides.


Then the third side is  (2x-8), and you have this equation for the perimeter


    x + x + (2x-8) = 40.

   
From the equation


    4x - 8 = 40

    4x     = 40 + 8 = 48

     x              = 48/4 = 12.


<U>ANSWER</U>.  The sides are  12 units, 12 units and  2*12-4 = 20 units long.
</pre>

Solved.


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I remember your previous version, mistakenly written.


Glad that you found and fixed your error.