document.write( "Question 251882: Please help me solve this problem: (squareroot)x^2/18 both the numerator and denominator are under one square root sign. \r
\n" ); document.write( "\n" ); document.write( "the instructions say to rationalize the denominator.\r
\n" ); document.write( "\n" ); document.write( "Becasue 18's square root is 4.24 I am unsure this is the right answer (x/4.24) I believe I may be missing something. Should I factor out the denominator?
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Algebra.Com's Answer #183582 by solver91311(24713)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "In the first place 18's square root is NOT 4.24. 4.24 is only an approximation of the square root of 18. You cannot exactly represent the square root of 18 with a decimal fraction. If you could exactly represent the square root of 18 with some decimal fraction, then the square root of 18 would have to be rational -- that is because any decimal fraction with a finite number of decimal places can be represented exactly by the quotient of two integers. But we can prove that 18 is not rational...\r
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\n" ); document.write( "\n" ); document.write( "The first thing to do is to find the prime factorization of 18, namely 2 times 3 times 3. Take two factors of 3 out of the radical and leave one of them on the outside, hence:\r
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\n" ); document.write( "\n" ); document.write( "Now your problem looks like:\r
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\n" ); document.write( "\n" ); document.write( "So far, so good, but we still have a radical (irrational number) in the denominator. It would be tidy if we were able to multiply the denominator by , but that would change the value of the fraction. However, we can multiply the entire fraction by 1 and not change its value. So let's multiply by 1 in the form of , thus:\r
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\n" ); document.write( "\n" ); document.write( "Now you have an equivalent representation of the original expression with a rational number denominator.\r
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\n" ); document.write( "\n" ); document.write( "See my lesson on Rationalizing Denominators:\r
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\n" ); document.write( "\n" ); document.write( "http://www.algebra.com/algebra/homework/Radicals/rationalizingdenominators1.lesson\r
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\n" ); document.write( "\n" ); document.write( "John
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