document.write( "Question 1188466: The radical \"+sqrt%2894%2Bsqrt%281440%29%29+\" can be expressed as \"+sqrt%28a%29%2Bsqrt%28b%29+\", where \"+a%3Cb+\". What is the product ab? \n" ); document.write( "
Algebra.Com's Answer #819567 by mccravyedwin(407)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Ikleyn misinterpreted the problem.  This is a common type problem of simplifying\r\n" );
document.write( "expressions involving square roots occurring under square roots.  While she is\r\n" );
document.write( "right that there are an infinite number of values of a and b which would make\r\n" );
document.write( "the equation\r\n" );
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document.write( "\"sqrt%2894%2Bsqrt%281440%29%29\"\"%22%22=%22%22\"\"sqrt%28a%29%2Bsqrt%28b%29\"\r\n" );
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document.write( "true, this is not what is asked for.  What is being asked for is to find two\r\n" );
document.write( "simple numbers, hopefully, positive integers, a and b, which will make the expression\r\n" );
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document.write( "\"sqrt%2894%2Bsqrt%281440%29%29\"\r\n" );
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document.write( "exactly equivalent to a simpler expression in the form\r\n" );
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document.write( "\"sqrt%28a%29%2Bsqrt%28b%29\"\r\n" );
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document.write( "----------------------------------------------------------------------------\r\n" );
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document.write( "However, instead of doing your homework for you, I'll instead do one exactly\r\n" );
document.write( "step-by-step like yours that you can follow as a model when solving yours. Here\r\n" );
document.write( "is the problem I will do for you that is exactly like yours in every way:\r\n" );
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The radical \"sqrt%2899%2Bsqrt%282232%29%29+\" can be expressed as
\n" ); document.write( "\"sqrt%28a%29%2Bsqrt%28b%29+\", where \"a%3Cb\". What is the product ab?
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document.write( "\"sqrt%2899%2Bsqrt%282232%29%29\"\"%22%22=%22%22\"\"sqrt%28a%29%2Bsqrt%28b%29\"\r\n" );
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document.write( "Square both sides:\r\n" );
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document.write( "equation (1):    \"99%2Bsqrt%282232%29\"\"%22%22=%22%22\"\"a%2B2sqrt%28ab%29%2Bb\"\r\n" );
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document.write( "In equation (1), set the term WITHOUT a square root on the left equal to the sum\r\n" );
document.write( "of the terms WITHOUT square roots on the right:\r\n" );
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document.write( "\"99\"\"%22%22=%22%22\"\"a%2Bb\"\r\n" );
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document.write( "In equation (1), set the term WITH a square root on the left equal to the term\r\n" );
document.write( "WITH a square root on the right:\r\n" );
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document.write( "\"sqrt%282232%29\"\"%22%22=%22%22\"\"2sqrt%28ab%29\"\r\n" );
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document.write( "Square both sides:\r\n" );
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document.write( "\"2232\"\"%22%22=%22%22\"\"4ab\"\r\n" );
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document.write( "\"558\"\"%22%22=%22%22\"\"ab\"  <---answer!\r\n" );
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document.write( "That's the answer you were asked for.  \r\n" );
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document.write( "But in other problems, you WILL be asked to find a and b.  So I will continue\r\n" );
document.write( "to find the values of a and b:\r\n" );
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document.write( "Solve the system of equations:\r\n" );
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document.write( "\"system%28a%2Bb=99%2Cab=558%29\"\r\n" );
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document.write( "Solve the first equation for b:\r\n" );
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document.write( "\"a%2Bb\"\"%22%22=%22%22\"\"99\"\r\n" );
document.write( "\"b\"\"%22%22=%22%22\"\"99-a\"\r\n" );
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document.write( "Substitute in the second equation in the system \r\n" );
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document.write( "\"a%2899-a%29\"\"%22%22=%22%22\"\"558\"\r\n" );
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document.write( "\"99a-a%5E2\"\"%22%22=%22%22\"\"558\"\r\n" );
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document.write( "\"-a%5E2%2B99a-558\"\"%22%22=%22%22\"\"0\"\r\n" );
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document.write( "\"a%5E2-99a%2B558\"\"%22%22=%22%22\"\"0\"\r\n" );
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document.write( "\"%28a-6%29%28a-93%29\"\"%22%22=%22%22\"\"0\"\r\n" );
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document.write( "a-6 = 0;   a-93 = 0\r\n" );
document.write( "  a = 6;      a = 93\r\n" );
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document.write( "\"b\"\"%22%22=%22%22\"\"99-a\"\r\n" );
document.write( "For a = 6         For a = 93\r\n" );
document.write( "\"b\"\"%22%22=%22%22\"\"99-6\"     \"b\"\"%22%22=%22%22\"\"99-93\"\r\n" );
document.write( "\"b\"\"%22%22=%22%22\"\"93\"       \"b\"\"%22%22=%22%22\"\"6\"\r\n" );
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document.write( "Since a < b, we choose a = 6 and b = 93\r\n" );
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document.write( "So the radical expression \"sqrt%2899%2Bsqrt%282232%29%29+\" can be expressed as \r\n" );
document.write( "\"sqrt%286%29%2Bsqrt%2893%29+\", where \"a%3Cb\"\r\n" );
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document.write( "Now do yours the exact same way, step-by-step.\r\n" );
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document.write( "Edwin
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