document.write( "Question 246678: log[3](1-x)+log[3](2-x)=log[3](7) the numbers in brackets are the bases. Please help \n" ); document.write( "
Algebra.Com's Answer #180053 by nerdybill(7384)\"\" \"About 
You can put this solution on YOUR website!
log[3](1-x)+log[3](2-x)=log[3](7)
\n" ); document.write( "log[3](1-x)(2-x)=log[3](7)
\n" ); document.write( "(1-x)(2-x)=7
\n" ); document.write( "2-x-2x+x^2=7
\n" ); document.write( "2-3x+x^2=7
\n" ); document.write( "x^2-3x+2=7
\n" ); document.write( "x^2-3x-5=0
\n" ); document.write( "Applying the quadratic equation will yield:
\n" ); document.write( "x = {4.193, -1.193}
\n" ); document.write( "Checking for extraneous solutions:
\n" ); document.write( "We can throw out the 4.193 solution because it will give us a negative log. So:
\n" ); document.write( "x = {-1.193}
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\n" ); document.write( "Details of quadratic to follow:
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Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation \"ax%5E2%2Bbx%2Bc=0\" (in our case \"1x%5E2%2B-3x%2B-5+=+0\") has the following solutons:
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\n" ); document.write( " \"x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"
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\n" ); document.write( " For these solutions to exist, the discriminant \"b%5E2-4ac\" should not be a negative number.
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\n" ); document.write( " First, we need to compute the discriminant \"b%5E2-4ac\": \"b%5E2-4ac=%28-3%29%5E2-4%2A1%2A-5=29\".
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\n" ); document.write( " Discriminant d=29 is greater than zero. That means that there are two solutions: \"+x%5B12%5D+=+%28--3%2B-sqrt%28+29+%29%29%2F2%5Ca\".
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\n" ); document.write( " \"x%5B1%5D+=+%28-%28-3%29%2Bsqrt%28+29+%29%29%2F2%5C1+=+4.19258240356725\"
\n" ); document.write( " \"x%5B2%5D+=+%28-%28-3%29-sqrt%28+29+%29%29%2F2%5C1+=+-1.19258240356725\"
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\n" ); document.write( " Quadratic expression \"1x%5E2%2B-3x%2B-5\" can be factored:
\n" ); document.write( " \"1x%5E2%2B-3x%2B-5+=+1%28x-4.19258240356725%29%2A%28x--1.19258240356725%29\"
\n" ); document.write( " Again, the answer is: 4.19258240356725, -1.19258240356725.\n" ); document.write( "Here's your graph:
\n" ); document.write( "\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-3%2Ax%2B-5+%29\"

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