document.write( "Question 1189763: Given that x and y are integers and \"+sqrt%28+2sqrt%28+10+%29+%2B+11+%29+=+x+%2B+sqrt%28+x+%2B+y+%29+\", find x - y. \n" ); document.write( "
Algebra.Com's Answer #821237 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "Consider the general expansion

\n" ); document.write( "\"%28a%2Bsqrt%28b%29%29%5E2=%28a%5E2%2Bb%29%2B2a%28sqrt%28b%29%29\"

\n" ); document.write( "You can use that pattern to attempt to find the value of an expression of the form

\n" ); document.write( "\"sqrt%28m%2Bsqrt%28n%29%29\"

\n" ); document.write( "In this problem, the expression under the radical on the left is

\n" ); document.write( "\"2%2Asqrt%2810%29%2B11\" or \"11%2B2%2Asqrt%2810%29\"

\n" ); document.write( "According to the pattern above, we should have \"a%5E2%2Bb=11\", \"a=1\", and \"b=10\".

\n" ); document.write( "And those are all satisfied when a=1 and b=10. So

\n" ); document.write( "\"sqrt%2811%2B2%2Asqrt%2810%29%29+=+1%2Bsqrt%2810%29\"

\n" ); document.write( "Replacing the left side of the given equation with that gives us

\n" ); document.write( "\"1%2Bsqrt%2810%29=x%2Bsqrt%28x%2By%29\"

\n" ); document.write( "Solving by equating the rational and irrational parts of the two expressions gives us x=1 and y=9; so then

\n" ); document.write( "ANSWER: x-y = -8

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