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| 1. |
If a+b+c = 12 , A2 + b² +c2, find a³ +b³+c³-3abc |
| Answer» CORRECT OPTION isB108a+b+C=9 and a 2 +b 2 +c 2 =35Using formula,(a+b+c) 2 =a 2 +b 2 +c 2 +2(ab+bc+ca)9 2 =35+2(ab+bc+ca)2(ab+bc+ca)=81−35=46(ab+bc+ca)=23using formula, (a 3 +b 3 +c 3 )−3abc=(a 2 +b 2 +c 2 −ab−bc−ca)(a+b+c)a 3 +b 3 +c 3 −3abc=(35−23)×9=9×12=108 | |