document.write( "Question 1206117: Hello, I need help solving this equation. I am supposed to show all steps to solve for x. \r
\n" ); document.write( "\n" ); document.write( "log_(3)x+log_(3)(x+5)=9
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Algebra.Com's Answer #843354 by math_tutor2020(3817)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "\"log%283%2C%28x%29%29%2Blog%283%2C%28x%2B5%29%29+=+9\"\r
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\n" ); document.write( "\n" ); document.write( "\"log%283%2C%28x%28x%2B5%29%29%29+=+9\" use log rule that log(A)+log(B) = log(A*B)\r
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\n" ); document.write( "\n" ); document.write( "\"x%28x%2B5%29+=+3%5E9\" convert from log form to exponent form\r
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\n" ); document.write( "\n" ); document.write( "\"x%28x%2B5%29+=+19683\"\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B5x+=+19683\"\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B5x-19683+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "Apply the quadratic formula where a = 1, b = 5, c = -19683
\n" ); document.write( "\"x+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-5%2B-sqrt%28%285%29%5E2-4%281%29%28-19683%29%29%29%2F%282%281%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-5%2B-sqrt%2825+%2B+78732%29%29%2F%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-5%2B-sqrt%2878757%29%29%2F%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-5%2Bsqrt%2878757%29%29%2F%282%29\" or \"x+=+%28-5-sqrt%2878757%29%29%2F%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+137.818388\" or \"x+=+-142.818388\" both of which are approximate\r
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\n" ); document.write( "\n" ); document.write( "Since the domain of log(x) is x > 0, it rules out \"x+=+%28-5-sqrt%2878757%29%29%2F%282%29+=+-142.818388\" as a possible solution.\r
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\n" ); document.write( "\n" ); document.write( "Therefore, we go with \"x+=+%28-5%2Bsqrt%2878757%29%29%2F%282%29+=+137.818388\" as the only possible solution.\r
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\n" ); document.write( "\n" ); document.write( "I used WolframAlpha to confirm the answer is correct.
\n" ); document.write( "https://www.wolframalpha.com/input?i=log_%283%29x%2Blog_%283%29%28x%2B5%29%3D9\r
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\n" ); document.write( "\n" ); document.write( "Another way to confirm the answer is to let
\n" ); document.write( "f(x) = log(x)/log(3) + log(x+5)/log(3)
\n" ); document.write( "Note the use of the change of base formula.
\n" ); document.write( "Then you should find that f(137.818388) = 9 approximately.
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