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MHT CET20226 Aug 2022Morning ShiftMathematicsMatricesActual

If A= [ array lll 1 & a & 3 1 & 1 & 5 2 & 4 & 7 array ] and A⁻¹= [ array ccc 13 & 2 & -7 -3 & b & 2 -2 & 0 & 1 array ] , then the values of a and b are respectively

Options

  1. A2,-1
  2. B1,2
  3. C2,1
  4. D-1,2

Correct answer

A. 2,-1

Step-by-step solution

|A|=1 (7-20)-a(10-7)+3(4-2)=3 a-7 Now -3=- -3 3 a-7 a=2 Also b = 7-6 3 a -7 = 1 3 2-7 =-1 Hence a =2 and b =-1

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