InterviewSolution
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InterviewSolution
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यदि `x+y+z=6` और `x^(2)+y^(2)+z^(2)=20` है तो `x^(3)+y^(3)+z^(3)-3xyz` का मान ज्ञात करें।A. 64B. 70C. 72D. 76 |
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Answer» Correct Answer - C `x+y+z=6` `x^(2)+y^(2)+z^(2)=20` `implies (x+y+z)^(2)=(6)^(2)` `implies x^(2)+y^(2)+z^(2)+2(xy+yz+zx)=36` `implies 20+2(xy+yz+zx)=36` `implies 2(xy+yz+zx)=16` `xy+yz+zx=8` `implies x^(3)+y^(3)+z^(3)-3xyz=` `(x+y+z)(x^(2)+y^(2)+z^(2)-xy-zx-yz)` `implies x^(3)+y^(3)+z^(3)-3xyz=6(20-8)` `=6xx12=72` |
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