MHT CET202016 Oct 2020Morning ShiftMathematicsMatricesActual
If A= [ array ccc 2 & 0 & -1 5 & 1 & 0 0 & 1 & 3 array ] and A⁻¹= [ array ccc 3 & -1 & 1 & 6 & -5 & -2 & 2 array ] , then the values of and are. respectively
Options
- A15, 5
- B-15,5
- C15,-5
- D-15,-5
Correct answer
B. -15,5
Step-by-step solution
(B) We know, array l A A ⁻¹= I [ array ccc 2 & 0 & -1 5 & 1 & 0 0 & 1 & 3 array ] [ array ccc 3 & -1 & 1 & 6 & -5 & -2 & 2 array ]= [ array lll 1 & 0 & 0 0 & 1 & 0 0 & 0 & 1 array ] [ array ccc 6+0- & -2+0+2 & 2+0-2 15+ +0 & -5+6+0 & 5-5+0 0+ +3 & 0+6-6 & 0-5+6 array ]= [ array lll 1 & 0 & 0 0 & 1 & 0 0 & 0 & 1 array ] [ array ccc 6- & 0 & 0 15+ & 1 & 0 +3 & 0 & 1 array ]= [ array ccc 1 & 0 & 0 0 & 1 & 0 0 & 0 & 1 array ] 6- =1 =5 and 15+ =0 =-15 array This problem can also be solved as follows : We have A= [ array