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If g x = x 2 + x - 1 and g o f x = 4 x 2 - 10 x + 5 , then f 5 4 is equal to

Options

  1. A3 2
  2. B- 1 2
  3. C1 2
  4. D- 3 2

Correct answer

B. - 1 2

Step-by-step solution

g f x = 4 5 4 2 - 10 . 5 4 + 5 = - 5 4 g f 5 4 = f 2 5 4 + f 5 4 - 1 - 5 4 = f 2 5 4 + f 5 4 - 1 f 2 5 4 + f 5 4 + 1 4 = 0 f 5 4 + 1 2 2 = 0 f 5 4 = - 1 2

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