if a+b +c=9 and ab+bc+ca=26, find the value of a^3 +b^3 + c^3 -3abc​

1 thought on “if a+b +c=9 and ab+bc+ca=26, find the value of a^3 +b^3 + c^3 -3abc​”

1. Answer:

   Answer

   Correct option is

   D

   29

   Given, a+b+c=9 and ab+bc+ca=26.

   We know, (a+b+c)

   2

   =a

   2

   +b

   2

   +c

   2

   +2ab+2bc+2ca

   ⇒(a+b+c)

   2

   =a

   2

   +b

   2

   +c

   2

   +2(ab+bc+ca).

   Putting the values here, we get,

   (9)

   2

   =a

   2

   +b

   2

   +c

   2

   +2(26)

   ⇒81=a

   2

   +b

   2

   +c

   2

   +52

   ⇒a

   2

   +b

   2

   +c

   2

   =81−52=29.

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