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MHT CET202012 Oct 2020Morning ShiftMathematicsProperties of TrianglesActual

With usual notations, in ABC , if a =2, ~b =3, c =5 and A a + B b + C c = k+7 30 , then k =

Options

  1. A6
  2. B16
  3. C17
  4. D12

Correct answer

D. 12

Step-by-step solution

a=2, b=3, c=5 and A a + B b + C c = k+7 30 b²+c²-a² 2 a b c + a²+c²-b² 2 a b c + a²+b²-c² 2 a b c = k+7 30 b²+c²-a²+a²+c²-b²+a²+b²-c² 2 a b c = k+7 30 aligned a²+b²+c² 2 a b c &= k+7 30 2²+3²+5² 2 2 3 5 = k+7 30 38 30 60 &=k+7 19-7=k k &=12 aligned

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