If a3 + b3 = 35 and ab = 6, then what is the value of a + b? fro

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 Multiple Choice QuestionsMultiple Choice Questions

241.

If straight x space plus space 1 over straight x space equals space 4 comma space then what is the value of straight x to the power of 6 space plus space 1 over straight x to the power of 6 ?

  • 52

  • 256

  • 1026

  • 2702


242.

If straight y space equals space fraction numerator 2 minus straight x over denominator 1 plus straight x end fraction comma then what is the value of fraction numerator 1 over denominator straight y space plus space 1 end fraction space plus space fraction numerator 2 straight y space plus space 1 over denominator straight y squared minus 1 end fraction ?

  • fraction numerator left parenthesis 1 space plus space straight x right parenthesis thin space left parenthesis 2 space minus space straight x right parenthesis over denominator 2 straight x minus 1 end fraction

  • fraction numerator left parenthesis 1 space minus space straight x right parenthesis thin space left parenthesis 2 space plus space straight x right parenthesis over denominator straight x space minus space 1 end fraction

  • fraction numerator left parenthesis 1 space plus space straight x right parenthesis thin space left parenthesis 2 space minus space straight x right parenthesis over denominator 1 space minus space 2 straight x end fraction

  • fraction numerator left parenthesis 1 plus straight x right parenthesis thin space left parenthesis 1 minus 2 straight x right parenthesis over denominator 2 minus straight x end fraction


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243.

If a3 + b3 = 35 and ab = 6, then what is the value of a + b?

  • 5

  • 8

  • 2

  • -8


A.

5

Let a + b = x
C.B.S.
(a + b)3 = a3 + b3 + 3ab(a + b)
  ⟹  x3 = 35 + 3 x 6 x (x)
⟹   x3 - 18x = 35
⟹    x(x2 - 18) = 5 x 7
check with the option,
Now,
⟹    x = 5,   x2 -18 = 7
∴   a + b = 5




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244.

If (x - 2)2 + (y + 3)2 + (z - 15)2 = 0, then what is the value of x + y + z - 5?

  • 5

  • 9

  • 15

  • 20


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