 Hello friends, welcome to the session. I am Malika. We are going to discuss matrices. A given question is, assume x, y, z, w, n, p, r matrices of order 2 cross n, 3 cross k, 2 cross p, n cross 3, and p cross k respectively. Choose the correct answer in exercises 21 and 22. 22 is, if n equal to p, then the order of matrix 7x minus phi z is a p cross z, b, 2 cross n, c, n cross 3, d, p cross n. Now let's start with the solution. We are given order of matrix x equal to 2 cross n. Therefore, order of matrix 7x will be 2 cross n as it is scalar multiple of x. Now, order of matrix z equal to 2 cross p. Therefore, order of matrix minus phi z will also be 2 cross p as it is scalar multiple of z. Now as we know that addition of matrices is possible only when they have the same order. Therefore, order of 7x equal to order of minus phi z that is 2 cross n equal to 2 cross p. Hence, order of result in matrix that is 7x minus phi z is also either 2 cross n or 2 cross p since p equal to n this is given to us. Therefore, answer is b that is 2 cross n be the order of matrix 7x minus phi z. Hope you understood the solution and enjoyed the session. Goodbye and take care.