French, asked by DarThWadEr, 9 months ago

SI X + Y = 9, et XY = 25 trouvez x ^ 2 + y ^ 2.​

Answers

Answered by ksonakshi70
2

Answer:

(x + y) {}^{2}  = x {}^{2}  + y {}^{2}  + 2 \times x \times y \\ 9 {}^{2}  = x {}^{2}  + y {}^{2}  + 2 \times 25 \\ x {}^{2}  +   y {}^{2} + 81  = 50 \\ x {}^{2}  + y {}^{2}  = 50 - 81 =  \:  - 29

Answered by AdorableMe
37

◙ Il est donné que, ◙

x + y = 9 et xy = 25.

◙ Pour trouver ◙

La valeur de x² + y².

◙ Solution ◙

Nous savons,

x² + y² = (x + y) ² - 2xy

⇒x² + y² = (9) ² - 2 (25)

⇒x² + y² = 81 - 50

\underline{\huge\bold{\boxed{x^2+y^2=31}}}

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