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If a+b=10 and a²+b²=58 find the value of a³+b³ |
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Answer» (a+b)=10 a²+b²= 58 We KNOW that (a+b)²=a²+b²+2AB (10)²=58+2ab 100=58+2ab 100-58= 2ab 42= 2ab 21= ab Now , (a+b)³=a³+b³+3ab(a+b) (10)³=a³+b³+3*21(10) 1000=a³+b³+63(10) 1000=a³+b³+630 1000-630=a³+b³ 370=a³+b³ @:-) |
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