1.

If a+b=10 and a²+b²=58 find the value of a³+b³

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

@:-)





Discussion

No Comment Found

Related InterviewSolutions