SOLUTION: If (x+y)^2=200 and (x-y)^2=100 what is the average of x and y?

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Question 1128638: If (x+y)^2=200 and (x-y)^2=100 what is the average of x and y?
Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
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If  %28x%2By%29%5E2 = 200,  then  x+y = +/-sqrt%28200%29 = +/-10%2Asqrt%282%29.


Then the average of x and y is  %28x%2By%29%2F2 = plus OR minus  5%2Asqrt%282%29.    ANSWER

The rest of the condition is IRRELEVANT and does not influence or change the answer.