document.write( "Question 554219: Please find the solution of: \"+sqrt%285x%2B1%29+%2B+sqrt%283x%2B4%29+=+sqrt%2816x%2B9%29+\" \n" ); document.write( "
Algebra.Com's Answer #361276 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( " \"+sqrt%285x%2B1%29\" + \"sqrt%283x%2B4%29\" = \"sqrt%2816x%2B9%29+\"\r\n" );
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document.write( "To make things easier, let the radicals be letters and only\r\n" );
document.write( "replace them when they get squared: \r\n" );
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document.write( "let A =  \"+sqrt%285x%2B1%29\", B = \"sqrt%283x%2B4%29\", C = \"sqrt%2816x%2B9%29\"\r\n" );
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document.write( "then A² = 5x+1, B² = 3x+4, C² = 16x+9  \r\n" );
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document.write( "Since A and B are on the same side they will be multiplied, so\r\n" );
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document.write( "(AB)² = (5x+1)(3x+4) = 15x² + 23x + 4 \r\n" );
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document.write( "The original problem becomes\r\n" );
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document.write( "                A + B = C \r\n" );
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document.write( "Square both sides:\r\n" );
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document.write( "             (A + B)² = C²\r\n" );
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document.write( "        A² + 2AB + B² = 16x + 9\r\n" );
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document.write( "5x + 1 + 2AB + 3x + 4 = 16x + 9\r\n" );
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document.write( "         8x + 5 + 2AB = 16x + 9\r\n" );
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document.write( "                  2AB = 8x + 4\r\n" );
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document.write( "                   AB = 4x + 2\r\n" );
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document.write( "                (AB)² = (4x + 2)²\r\n" );
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document.write( "       15x² + 23x + 4 = 16x² + 16x + 4  \r\n" );
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document.write( "                    0 = x² - 7x            \r\n" );
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document.write( "                    0 = x(x - 7)\r\n" );
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document.write( "                        x = 0;  x - 7 = 0\r\n" );
document.write( "                                    x = 7\r\n" );
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document.write( "We must check both 0 and 7 for irrational solutions:                         \r\n" );
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document.write( "Checking x = 0\r\n" );
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document.write( "    \"+sqrt%285x%2B1%29\" + \"sqrt%283x%2B4%29\" = \"sqrt%2816x%2B9%29+\"\r\n" );
document.write( " \"+sqrt%285%280%29%2B1%29\" + \"sqrt%283%280%29%2B4%29\" = \"sqrt%2816%280%29%2B9%29+\"\r\n" );
document.write( "      \"+sqrt%280%2B1%29\" + \"sqrt%280%2B4%29\" = \"sqrt%280%2B9%29+\"\r\n" );
document.write( "          \"+sqrt%281%29\" + \"sqrt%284%29\" = \"sqrt%289%29+\"\r\n" );
document.write( "            1 + 2 = 3\r\n" );
document.write( "                3 = 3\r\n" );
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document.write( "So x = 0 is a solution \r\n" );
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document.write( "Checking x = 7\r\n" );
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document.write( "    \"+sqrt%285x%2B1%29\" + \"sqrt%283x%2B4%29\" = \"sqrt%2816x%2B9%29+\"\r\n" );
document.write( " \"+sqrt%285%287%29%2B1%29\" + \"sqrt%283%287%29%2B4%29\" = \"sqrt%2816%287%29%2B9%29+\"\r\n" );
document.write( "    \"+sqrt%2835%2B1%29\" + \"sqrt%2821%2B4%29\" = \"sqrt%28112%2B9%29+\"\r\n" );
document.write( "        \"+sqrt%2836%29\" + \"sqrt%2825%29\" = \"sqrt%28121%29+\"\r\n" );
document.write( "            6 + 5 = 11\r\n" );
document.write( "               11 = 11\r\n" );
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document.write( "So x = 7 is also a solution\r\n" );
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document.write( "So x = 0 and x = 7 are the solutions.   \r\n" );
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document.write( "Edwin
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