document.write( "Question 104689: Could someone please assist me by solving this logarithmic equation step-by-step for future reference. Thank you.\r
\n" ); document.write( "\n" ); document.write( "log(7y + 1) = 2log(y+3)-log2\r
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Algebra.Com's Answer #76196 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
Some rules to remember
\n" ); document.write( "\"k+log+%28x%29=log%28%28x%5Ek%29%29\"
\n" ); document.write( "\"log%28%28x%29%29%2Blog%28%28y%29%29=log%28%28xy%29%29\"
\n" ); document.write( "\"log%28%28x%29%29-log%28%28y%29%29=log%28%28x%2Fy%29%29\"
\n" ); document.write( "Now let's look at your example.
\n" ); document.write( "\"log%28%287y+%2B+1%29%29+=+2log%28%28y%2B3%29%29-log%28%282%29%29\"
\n" ); document.write( "\"log%28%287y+%2B+1%29%29+-+2log%28%28y%2B3%29%29=+-log%28%282%29%29\" Bring the variable expressions to one side.
\n" ); document.write( "\"log%28%287y+%2B+1%29%29+-+log%28%28y%2B3%29%5E2%29=+log%28%282%5E%28-1%29%29%29\" Power rule from above both sides.
\n" ); document.write( "\"log%28%28%287y+%2B+1%29%2F%28y%2B3%29%5E2%29%29=+log%28%282%5E%28-1%29%29%29\" Division rule from above.
\n" ); document.write( "\"%287y+%2B+1%29%2F%28y%2B3%29%5E2=+1%2F2\" Inverse function both sides.
\n" ); document.write( "\"2%287y+%2B+1%29=%28y%2B3%29%5E2\" Multiply both sides by \"2%2A%28y%2B3%29%5E2\"
\n" ); document.write( "\"14y%2B2=y%5E2%2B6y%2B9\" Distribute and expand.
\n" ); document.write( "\"y%5E2-8y%2B7=0\"Group all terms on one side.
\n" ); document.write( "\"%28y-1%29%28y-7%29=0\" Factor the equation.
\n" ); document.write( "\"y=1\" and \"y=7\". Two solutions.
\n" ); document.write( "Verify your answer
\n" ); document.write( "\"log%28%287y+%2B+1%29%29+=+2log%28%28y%2B3%29%29-log%28%282%29%29\"
\n" ); document.write( "\"log%28%287%281%29+%2B+1%29%29+=+2log%28%281%2B3%29%29-log%28%282%29%29\"
\n" ); document.write( "\"log%28%288%29%29=2log%28%284%29%29-log%28%282%29%29\"
\n" ); document.write( "\"log%28%288%29%29=log%28%284%5E2%2F2%29%29\" Power and division rule, right hand side.
\n" ); document.write( "\"log%28%288%29%29=log%28%288%29%29\"
\n" ); document.write( "Good answer.
\n" ); document.write( "\"log%28%287y+%2B+1%29%29+=+2log%28%28y%2B3%29%29-log%28%282%29%29\"
\n" ); document.write( "\"log%28%287%287%29+%2B+1%29%29+=+2log%28%287%2B3%29%29-log%28%282%29%29\"
\n" ); document.write( "\"log%28%2850%29%29=2log%28%2810%29%29-log%28%282%29%29\"
\n" ); document.write( "\"log%28%2850%29%29=log%28%2810%5E2%2F2%29%29\" Power and division rule, right hand side.
\n" ); document.write( "\"log%28%2850%29%29=log%28%2850%29%29\"
\n" ); document.write( "Good answer.
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