If x - y=7 and xy=9 find the value of x square+ y square
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x-y = 7 -------(1)
xy = 9 -------(2)
We know that,
(x-y) ^2 = x^2 + y^2 - 2xy
=> 7^2 = x^2 + y^2 - 2(9)
=> 49 = x^2 +y^2 - 18
=> x^2 + y^2 = 49 + 18
=> x^2 + y^2 = 67
xy = 9 -------(2)
We know that,
(x-y) ^2 = x^2 + y^2 - 2xy
=> 7^2 = x^2 + y^2 - 2(9)
=> 49 = x^2 +y^2 - 18
=> x^2 + y^2 = 49 + 18
=> x^2 + y^2 = 67
CRM:
Thx a lot,very useful
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