 Hello friends, welcome to the session. I am Malka and we are going to discuss matrices if a which is our first matrix is 2 by 3 1 5 by 3 1 by 3 2 by 3 4 by 3 7 by 3 2 2 by 3 and a second matrix Which is b is 2 by 5 3 by 5 1 1 by 5 2 by 5 4 by 5 7 by 5 6 by 5 2 by 5 then we have to compute 3a minus 5 b So now let's start with the solution From our question we see that we have to calculate 3a and minus of 5 b So first of all let us calculate the value of 3a Now we know that a equal to 2 by 3 1 5 by 3 1 by 3 2 by 3 4 by 3 7 by 3 2 and 2 by 3 and the value of b equal to 2 by 5 3 by 5 1 1 by 5 2 by 5 4 by 5 7 by 5 6 by 5 2 by 5 now we'll calculate the value of 3a So therefore 3a Equal to 3 multiplied by the matrix a 3 multiplied by 2 by 3 1 5 by 3 1 by 3 2 by 3 4 by 3 7 by 3 2 2 by 3 will give us This is equal to 3 Multiplied by 2 by 3 3 multiplied by 1 3 multiplied by 5 by 3 Similarly, we'll write for the second row and for the third row This is equal to 2 3 5 1 2 4 7 6 2 Now we'll calculate the value of 5b On multiplying 5 with the matrix B. We get 5 into 2 by 5 5 into 3 by 5 5 into 1 and similarly for second and third row This is equal to 2 3 5 1 2 4 7 6 2 Now we'll calculate minus 5b therefore minus 5b equal to minus 2 minus 3 minus 5 minus 1 minus 2 minus 4 minus 7 minus 6 minus 2 Now we'll calculate the value of 3a minus 5b Which is equal to 3a plus minus 5b Now on substituting the value of 3a and minus 5b We get 2 3 5 1 2 4 7 6 2 plus minus 2 minus 3 minus 5 minus 1 minus 2 minus 4 minus 7 minus 6 1 minus 1 This is equal to 0 0 0 0 0 0 0 0 Therefore the value of 3a minus 5b equal to 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0