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2 years ago

If x-y=9,x²+y²=27,then xy=?

Mathematics

1 answer:

Tresset [83]2 years ago

5 0

Answer:

xy = - 27

Step-by-step explanation:

Note that

(x - y)² = x² - 2xy + y² ← substitute given values, that is

9² = 27 - 2xy

81 = 27 - 2xy ( subtract 27 from both sides )

54 = - 2xy (divide both sides by - 2 )

- 27 = xy

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If x-y=9,x²+y²=27,then xy=?​

If x-y=9,x²+y²=27,then xy=?