Question 414718
{{{H^2 = leg1^2 + leg2^2}}}
{{{(3x+1)^2 = x^2 + (3x-1)^2}}}
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{{{(3x+1)^2 - (3x-1)^2 = x^2}}}
{{{6x*2 = x^2}}}
{{{x^2 - 12x = 0}}}
x = 0, 12 Ignore the zero
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x = 12
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12^2 + 35^2 = 37^2
That works.