SOLUTION: if x+y=8 and xy=7, find the value of x^2+y^2

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Question 940167: if x+y=8 and xy=7, find the value of x^2+y^2
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
xy=7, y+=+7%2Fx
x%2B7%2Fx+=8+ |Multiplying thru by x so as all denominators = 1
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x^2 + 7 = 8x
x^2 - 8x + 7 = 0
(x-7)(x-1)= 0
x = 1,7 and y = 7, 1
P(1,7) and P(7,1)
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x^2 + y^2 = 50