Answer:
c.
Explanation:
that is easy.
a matrix multiplied by a constant is multiplying every element in the matrix by that constant.
and subtracting a matrix from another is subtracting the elements on each position.
it is a simile as that.
for that reason I only need to look at the first, top left element to determine the correct answer :
-1×2 - 4×7 = -2 - 28 = -30
so, c. is the right answer.
the calculation in full :
2A =
-2 18 4
20 -20 4
-10 12 -10
4B =
28 -4 -4
24 -16 -12
-40 40 -28
so, 2A - 4B =
-30 22 8
-4 -4 16
30 -28 18