InterviewSolution
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InterviewSolution
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यदि `a+b+c=15` और `a^(2)+b^(2)+c^(2)=83` है तो `a^(3)+b^(3)=83` है तो `a^(3)+b^(3)+c^(3)-3abc` का मान ज्ञात करें।A. 200B. 180C. 190D. 210 |
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Answer» Correct Answer - B `a+b+c=15` `a^(2)+b^(2)+c^(2)=83` `:.(a+b+c)^(2)=(15)^(2)` `implies a^(2)+b^(2)+c^(2)+2ab+2bc+2ca=225` `implies 83+2(ab+bc+ca)=225` `implies 2(ab+bc+ca)=225-83=142` `ab+bc+ca=71` `implies a^(3)+b^(3)+c^(3)-3abc=(a+b+c)(a^(2)+b^(2)+c^(2)-ab-bc-ca)` `implies a^(3)+b^(3)+c^(3)-3abc=15(83-71)=` `15xx12=180` |
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