Answer:
-1/3 (7 + 2 sqrt(10))
Explanation:
(sqrt(2)+sqrt(5))
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sqrt(2)- sqrt(5)
We need to multiply the top and bottom by the complex conjugate of the bottom. The complex conjugate of the bottom is sqrt(2) + sqrt(5)
(sqrt(2)+sqrt(5)) * (sqrt(2)+sqrt(5)
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(sqrt(2)- sqrt(5)) * (sqrt(2)+sqrt(5))
FOILing the top and bottom
(2+sqrt(10) + sqrt(10)+5)
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(2- sqrt(10) +sqrt(10)-5)
(7+2sqrt(10))
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-3
-1/3 (7 + 2 sqrt(10))