document.write( "Question 118001: express 5√72 in simplest radical form
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\n" ); document.write( "find the sum of: √120 + √75
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Algebra.Com's Answer #86045 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
#1\r
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\n" ); document.write( "\n" ); document.write( "\"5%2Asqrt%2872%29\" Start with the given expression\r
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\n" ); document.write( "\n" ); document.write( "Let's simplify \"sqrt%2872%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"sqrt%2872%29\" Start with the given expression\r
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\n" ); document.write( "\n" ); document.write( "The goal of simplifying expressions with square roots is to factor the radicand into a product of two numbers. One of these two numbers must be a perfect square. When you take the square root of this perfect square, you will get a rational number.\r
\n" ); document.write( "\n" ); document.write( "So let's list the factors of 72\r
\n" ); document.write( "\n" ); document.write( "Factors:\r
\n" ); document.write( "\n" ); document.write( "1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72\r
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\n" ); document.write( "\n" ); document.write( "Notice how 36 is the largest perfect square, so lets factor 72 into 36*2\r
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\n" ); document.write( "\n" ); document.write( "\"sqrt%2836%2A2%29\" Factor 72 into 36*2
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\n" ); document.write( "\"sqrt%2836%29%2Asqrt%282%29\" Break up the square roots using the identity \"sqrt%28x%2Ay%29=sqrt%28x%29%2Asqrt%28y%29\"
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\n" ); document.write( "\"6%2Asqrt%282%29\" Take the square root of the perfect square 36 to get 6
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\n" ); document.write( "So the expression \"sqrt%2872%29\" simplifies to \"6%2Asqrt%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "Now reintroduce the 5 to get \"5%2A6%2Asqrt%282%29\". Now multiply to get\r
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\n" ); document.write( "\n" ); document.write( "\"30%2Asqrt%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "So \"5%2Asqrt%2872%29\" simplifies to \"30%2Asqrt%282%29\"\r
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\n" ); document.write( "Check:\r
\n" ); document.write( "\n" ); document.write( "Notice if we evaluate \"5%2Asqrt%2872%29\" with a calculator we get\r
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\n" ); document.write( "\n" ); document.write( "\"5%2Asqrt%2872%29=42.4264068711929\"\r
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\n" ); document.write( "\n" ); document.write( "and if we evaluate \"30%2Asqrt%282%29\" we get\r
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\n" ); document.write( "\n" ); document.write( "\"30%2Asqrt%282%29=42.4264068711929\"\r
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\n" ); document.write( "\n" ); document.write( "This shows that \"5%2Asqrt%2872%29=30%2Asqrt%282%29\". So this verifies our answer \r
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\n" ); document.write( "\n" ); document.write( "#2\r
\n" ); document.write( "\n" ); document.write( "\"sqrt%28120%29%2Bsqrt%2875%29\" Start with the given expression\r
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\n" ); document.write( "\n" ); document.write( "\"sqrt%2815%2A8%29%2Bsqrt%2815%2A5%29\" Factor 120 into 15*8 and factor 75 into 15*5\r
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\n" ); document.write( "\n" ); document.write( "\"sqrt%2815%29%2Asqrt%288%29%2Bsqrt%2815%29%2Asqrt%285%29\" Break up the square roots\r
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\n" ); document.write( "\n" ); document.write( "\"sqrt%2815%29%28sqrt%288%29%2Bsqrt%285%29%29\" Factor out the common term of \"sqrt%2815%29\"\r
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\n" ); document.write( "\n" ); document.write( "So \"sqrt%28120%29%2Bsqrt%2875%29\" simplifies to \"sqrt%2815%29%28sqrt%288%29%2Bsqrt%285%29%29\"
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