# CBSE 12th Mathematics Board Exam 2020: Important Questions & Answers from Chapter 3 - Matrices

Check important questions and answers for Class 12th Mathematics Board Examination 2020 from Chapter 3 - Matrices.

Created On: Mar 16, 2020 13:04 IST
Matrices

The students who will be appearing for CBSE Class 12th Mathematics Examination 2020 on March 17, 2020, can go through the below-mentioned important questions for Chapter 3- Matrices. These Questions are based on the latest syllabus prescribed by the CBSE Board.

Question 1- If a matrix has 28 elements, what are the possible orders it can have? What if it has 13 elements?

Answer: If the matrix has 28 elements then, the possible orders are given by

1 x 28, 2 x 14, 4 x 7, 7 x 4, 14 x 2, 28 x 1

If it has 13 elements then, the possible orders are 1 x 13 and 13 x 1.

Question 2- Construct a2 x 2 matrix, where:

(i)aij = (i-2j)2 / 2  (ii) aij = |-2i+3j|

(i)

(ii)

Question 3- Find the values of a and b, if A = B, where

Answer: The value of a = 2 and b = 2.

Question 4- If possible, find the sum of the matrices A and B, where

Answer: Here, A and B are of different orders. We know that the addition of two matrices A and B is possible only if the order of both the matrices A and B should be the same.

Hence, the sum of matrices A and B is not possible.

Question 5- Find the non-zero value of x satisfying the matrix equation

Answer: The non-zero value of x satisfying the matrix equation is 4.

Question 6- Find the matrix A satisfying the matrix equation given below:

Answer: The matrix A will be:

Question 7- Find x, y and z, if the below-mentioned matrix, satisfies A’ = A-1

Question 8- Express the given matrix as the sum of a  symmetric and a skew-symmetric matrix.

Question 9- If possible, using elementary row transformations, find the inverse of the following matrices.

(ii) The second row of matrix A on LHS contains all zeroes, so, the inverse of matrix A does not exist.

(iii)

Question 10-  Find a matrix C such that 3A + 5B + 2C is a null matrix, where: