If x 2 + y 2 = 9 and xy = 8, then x + y is equal to 1. 25 2. 5 3. -5 4. ±5

We know that, . Substituting values we get, . Hence, Option 4 is the correct option.

Mathematics

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We know that,

$(x + y) = \sqrt{x^2 + y^2 + 2xy}$ .

Substituting values we get,

$(x + y) = \sqrt{9 + 2 \times 8} = \sqrt{9 + 16} = \sqrt{25} = \pm 5$ .

Hence, Option 4 is the correct option.

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