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SSC Selection Post 2020 PYQ — Question 54

SSC Selection Post - Matriculation Level 2020 - 9 Nov 2020 - Shift 1 • Quantitative Aptitude • Q54

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If x + y + z = 3 and xy + yz + zx = -11, then what is the value of x3 + y3 + z3 – 3xyz?
 

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Correct answer: A

Explanation

The correct answer is option 1 i.e. 126.

x3+y3+z3−3xyz=(x+y+z)3−3(x+y+z)(xy+yz+zx)x^3 + y^3 + z^3 - 3xyz = (x + y + z)^3 - 3(x + y + z)(xy + yz + zx)

=(3)3−3(3)(−11)=27+99=126= (3)^3 - 3(3)(-11)\\ = 27 + 99 =126