Question 878394
The sheet is x by 3x
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After it's cut, it's x-6 by 3x-6
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Vol = 3*(x-6)*(3x-6) = 189
(x-6)*(x-2) = 21  (make it easier)
{{{x^2 - 8x + 12 = 21}}}
{{{x^2 - 8x - 9 = 0}}}
x = 9  (Ignore the -1 solution)
--> 9 by 27