SOLUTION: solve algebraically x^2+y^2=17 x+y=5

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Question 806048: solve algebraically
x^2+y^2=17
x+y=5
Answer by mananth(16946) About Me  (Show Source):
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x^2+y^2=17
x+y=5
x^2+y^2+2xy-2xy =17
(x+y)^2-2xy =17
5^2-2xy=17
2xy=25-17
2xy=8
xy=4
y=4/x
x+(4/x)=5
x^2+4=5x
x^2-5x+4=0
x^2-4x-x+4=0
x(x-4)-1(x-4)=0
(x-4)(x-1)=0
x=4 OR 1
plug x to get y