document.write( "Question 130770: The flower garden has the shape of a right triangle. 20 ft. of a perennial border forms the hypotenuse of the triangle, and one leg is 4 ft longer than the other leg. Find the lengths of the legs.\r
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\n" ); document.write( "\n" ); document.write( "I was trying to set up using the pythagorean theorem and for some reason my answers keeps coming up as incorrect.\r
\n" ); document.write( "\n" ); document.write( "Setting up the problem as:\r
\n" ); document.write( "\n" ); document.write( "\"20%5E2+=+x%5E2+%2B+%28x+%2B+4%29%5E2\"\r
\n" ); document.write( "\n" ); document.write( "Am I doing something wrong?
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Algebra.Com's Answer #95479 by solver91311(24713)\"\" \"About 
You can put this solution on YOUR website!
\"20%5E2+=+x%5E2+%2B+%28x+%2B+4%29%5E2\" looks mighty good to me. Let's see where this takes us:\r
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\n" ); document.write( "\n" ); document.write( "I'll start by turning things around:
\n" ); document.write( "\"x%5E2+%2B+%28x+%2B+4%29%5E2=20%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "Expand and collect terms:
\n" ); document.write( "\"x%5E2%2B%28x%5E2%2B8x%2B16%29=400\"\r
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\n" ); document.write( "\n" ); document.write( "\"2x%5E2%2B8x%2B16=400\"\r
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\n" ); document.write( "\n" ); document.write( "Put in standard form (\"ax%5E2%2Bbx%2Bc=0\"
\n" ); document.write( "\"2x%5E2%2B8x%2B16-400=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"2x%5E2%2B8x-384=0\"\r
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\n" ); document.write( "\n" ); document.write( "Divide by the lead coefficient to get things in lowest terms:
\n" ); document.write( "\"x%5E2%2B4x-192=0\"\r
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\n" ); document.write( "\n" ); document.write( "Finally, factor the trinomial (or complete the square, or use the quadratic formula, according to your preference):
\n" ); document.write( "\"%28x-12%29%28x%2B16%29=0\", because \"-12%2A16=-192\" and \"-12%2B16=4\"\r
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\n" ); document.write( "\n" ); document.write( "This says that \"x=12\" or \"x=-16\", but we can exclude the negative root for two reasons. First, because we are looking for a measure of length, a negative number is absurd, and secondly, since in setting up the original equation you squared the variable, you introduced an extraneous root -- one that satisfies the derived equation, but does not satisfy the original problem.\r
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\n" ); document.write( "\n" ); document.write( "Therefore, the correct answer is that the short leg is 12 feet and the long leg is 16 feet.\r
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\n" ); document.write( "\n" ); document.write( "Check the answer:\r
\n" ); document.write( "\n" ); document.write( "\"12%5E2=144\", \"16%5E2=256\", \"144%2B256=400\", and \"sqrt%28400%29=20\". Answer checks.
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