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4 votes
X^{2} +y^{2} =?
cho mình hỏi với

User Jottbe
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1 Answer

5 votes

Answer:


{ \sf{ {x}^(2) + {y}^(2) = {(x + y)}^(2) - 2xy }}

Explanation:


{ \tt{ {(x + y)}^(2) = (x + y)(x + y) }} \\ { \tt{ {(x + y)}^(2) = ( {x}^(2) + 2xy + {y}^(2)) }} \\ { \tt{( {x}^(2) + {y}^(2) ) = {(x + y)}^(2) - 2xy}}

User Vishwadeep Singh
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