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MHT CET202020 Oct 2020Evening ShiftMathematicsQuadratic EquationActual

If f(x)=a x²+b x+2 and f(1)=4, f(3)=38 , then a-b=

Options

  1. A15
  2. B-2
  3. C2
  4. D8

Correct answer

D. 8

Step-by-step solution

array l f(1)=4 ; a+b=2...(1) f(3)=38 ; 9 a+3 b+2=38- (2) 3 a+b=12 array Solving (1) & (2) array l a=5, b=-3 a-b=8 array

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