document.write( "Question 740355: Solve the equation, give an exact solution\r
\n" ); document.write( "\n" ); document.write( "log4(x+4) + log4(x+4) = 1\r
\n" ); document.write( "\n" ); document.write( "I cannot figure out the answer. \n" ); document.write( "

Algebra.Com's Answer #451560 by MathLover1(20850) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"log%284%2C%28x%2B4%29%29+%2B+log%284%2C%28x%2B4%29%29+=+1\"$ ....in base $\"10\"$ we have\r
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\n" ); document.write( "\n" ); document.write( " $\"2log%28%28x%2B4%29%29%2Flog%284%29+=+1\"$ \r
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\n" ); document.write( "\n" ); document.write( " $\"2log%28%28x%2B4%29%29+=+1%2Alog%284%29\"$ \r
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\n" ); document.write( "\n" ); document.write( " $\"log%28%28x%2B4%29%5E2%29+=+log%284%29\"$ ...if so, then\r
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\n" ); document.write( "\n" ); document.write( " $\"%28x%2B4%29%5E2+=+4\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2%2B8x%2B16+=+4\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2%2B8x%2B16+-4=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x%5E2%2B8x%2B12=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+%28-8+%2B-+sqrt%28+8%5E2-4%2A1%2A12+%29%29%2F%282%2A1%29+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+%28-8+%2B-+sqrt%28+64-48+%29%29%2F2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+%28-8+%2B-+sqrt%28+16%29%29%2F2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+%28-8+%2B-+4%29%2F2+\"$ \r
\n" ); document.write( "\n" ); document.write( "solutions;\r
\n" ); document.write( "\n" ); document.write( " $\"x+=+%28-8+%2B-4%29%2F2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+-4%2F2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"highlight%28x+=+-2%29+\"$ .......\r
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\n" ); document.write( "\n" ); document.write( " $\"x+=+%28-8+-4%29%2F2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+-12%2F2+\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x+=+-6+\"$ \r
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\n" ); document.write( "\n" ); document.write( "we need only this solution because we have $\"logarithm\"$ and we can find only log of positive number; since we looking for log of $\"%28x%2B4%29\"$ it will be positive number if we plug in $\"x=-2\"$ ( $\"%28x%2B4%29=-2%2B4=2\"$ )\r
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\n" ); document.write( "\n" ); document.write( "if we plug in $\"x=-6\"$ we will get negative number ( $\"%28x%2B4%29=-6%2B4=-2\"$ )\r
\n" ); document.write( "\n" ); document.write( "so, your solution is: $\"highlight%28x+=+-2%29+\"$ \r
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