Question

Please show me the workings of this no.2?

Answer 1

This is direct scalar multiplication and then subtraction of matrices.

Explanation:

Scalar multiplication of matrices simply means that each element in the matrix is multiplied by the constant. So, each element in A will be multiplied by 2.

Then, matrix subtraction (and addition) is performed by element by element subtraction.

So, in this case, 2(-8) = -16. Then, you will subtract the 1 in the upper right corner of B to give -16 - 1 = -17.

So, a = 17

Answer 2

`-17`

Explanation:

Given that `A = ((2,1,color(green)(-8)),(-9,4,7),(-1,9,3),(1,4,1))`

Then `2A =((4,2,color(green)(-16)),(-18,8,14),(-2,18,6),(2,8,1))`

Given that `B=((3,3,color(red)(1)),(3,-3,-3),(7,-2,-4),(-9,1,-7))`

So for the element `a` we have:

`color(green)(color(white)("d")2A) - color(red)(B)`

`color(green)(-16)-color(red)(1) = -17`