document.write( "Question 1128638: If (x+y)^2=200 and (x-y)^2=100 what is the average of x and y? \n" ); document.write( "
Algebra.Com's Answer #745118 by ikleyn(52797)\"\" \"About 
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document.write( "If  \"%28x%2By%29%5E2\" = 200,  then  x+y = +/-\"sqrt%28200%29\" = +/-\"10%2Asqrt%282%29\".\r\n" );
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document.write( "Then the average of x and y is  \"%28x%2By%29%2F2\" = plus OR minus  \"5%2Asqrt%282%29\".    ANSWER\r\n" );
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