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CDS 2022 · PYQ · Algebra · medium

If a+b = 2 and 1/a + 1/b = 2, then what is the value of a³+b³?

  1. A.4
  2. B.8
  3. C.2✓ Correct
  4. D.6

Explanation

1/a+1/b = (a+b)/(ab) = 2/ab = 2, so ab = 1. a³+b³ = (a+b)³-3ab(a+b) = 8 - 3·1·2 = 2.
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