document.write( "Question 742292: Solve and check
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document.write( "a) log(3x+2)+log(x-1)=2
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document.write( "b)2log(x-1)=2+log100\r
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document.write( "Can you please help me out? Thanks so much in advance:)
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document.write( "Can you please show the work it will help me understand better:) thanks again \n" );
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Algebra.Com's Answer #452399 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! Solve and check \n" ); document.write( "a) log(3x+2) + log(x-1) = 2 \n" ); document.write( "Addition of logs means multiply \n" ); document.write( "log[(3x+2)*(x-1)] = 2 \n" ); document.write( "FOIL \n" ); document.write( "log(3x^2 - 3x + 2x - 2) = 2 \n" ); document.write( "log(3x^2 - x - 2) = 2 \n" ); document.write( "exponent equiv of logs \n" ); document.write( "3x^2 - x - 2 = 10^2 \n" ); document.write( "3x^2 - x - 2 = 100 \n" ); document.write( "3x^2 - x - 2 - 100 = 0 \n" ); document.write( "3x^2 - x - 102 = 0 \n" ); document.write( "Factors to \n" ); document.write( "(3x + 17)(x - 6) = 0 \n" ); document.write( "The positive solution is all we want here \n" ); document.write( "x = 6 \n" ); document.write( ": \n" ); document.write( "Check this out using a calc \n" ); document.write( "log(3(6)+2) + log(6-1) = 2 \n" ); document.write( "log(20) + log(5) = 2 \n" ); document.write( "1.3 + .7 = 2; confirms our solution of x=6 \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "b)2log(x-1) = 2 + log(100) \n" ); document.write( "we know the log of 100 is so we can write it \n" ); document.write( "2log(x-1) = 2 + 2 \n" ); document.write( "2log(x-1) = 4 \n" ); document.write( "log[(x-1)^2] = 4 \n" ); document.write( "Exponent equiv \n" ); document.write( "(x-1)^2 = 10^4 \n" ); document.write( "(x-1)^2 = 10000 \n" ); document.write( "find the square root of both sides \n" ); document.write( "x - 1 = \n" ); document.write( "x - 1 = 100 \n" ); document.write( "x = 100 + 1 \n" ); document.write( "x = 101 \n" ); document.write( ": \n" ); document.write( "I'll let you check this solution, replace x with 101: \n" ); document.write( " |