Please show me the workings of this no.2?

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2 Answers
Mar 7, 2018

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

Mar 7, 2018

#-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#