If (\x + \y) = 3, \xy = 2, then what is the value of \x^3 + \y^3

CMAT 2022 Solved Question Paper

Question : 20 of 100

Marks: +1, -0

(\x + \y) = 3, \xy = 2

, then what is the value of

\x^3 + \y^3

Solution:

Given,

\x+\y=3 \and \xy =2

\x^3 + \y^3 = (\x+\y) (\x^2+\y^2 - \xy)

\x+\y=3

squaring on both sides

(\x+\y)^2 = 9

\x^2+\y^2+2\xy=9

\x^2+\y^2=9-4=5

\x^3+\y^3=3(5=2)=9

Answer is option D.

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