Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
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

  1. A15, 5
  2. B-15,5
  3. C15,-5
  4. 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

Practice Matrices on Quantrex Academy →

More from Matrices

Given A = bmatrix x & 1 & -2 bmatrix and B = bmatrix 1 & 2 & 3 4 & 5 & 6 7 & 8 & 9 bmatrix . If ABA^t = [-20] then the value of x is: 2026If the matrix M = bmatrix x+5 & a & -4 -2 & 0 & b c & 6 & y+1 bmatrix is a skew symmetric matrix, the value of the expression ab + c^2 - xy is: 2026Matrix A = bmatrix 1 & 1 & 2 1 & -2 & 2 1 & 0 & -1 bmatrix , Given M₂₂ and A₃₂ are the minor and cofactor of the adjoint matrix of A respectively then the value of the expression M 2026If A and B are two square matrices of the same order such that AB = A and BA = B , then (A + B)^2 is equal to: 2026Given the matrices A = bmatrix 1 & 0 & 1 0 & 1 & 0 1 & 0 & 2 bmatrix and B = bmatrix 2 & 1 & 0 1 & 1 & 2 0 & 2 & 1 bmatrix , then the minor M₂₃ of the matrix (A B⁻¹)⁻¹ is: 2026Given A = pmatrix 1 & 2 2 & 3 pmatrix and f(x) = x^2 - 2x - 3 then f(A) is: 2026If the system of equations 2 x+p y+6 z=8, x+2 y+q z=5 and x+y+3 z=4 has infinitely many solutions, then p = 2025If x^a y^b=e^m, x^c y^d=e^n, ₁= | array ll m & b n & d array |, ₂= | array ll a & m c & n array |, ₃= | array ll a & b c & d array | , then the values of x and y are respectively ( 2025 Full Matrices list All MHT CET PYQs