Question

Let A, B, and C be matrices such that a= -5 1

      7 -4, b= -3 5

                    1 -6, and c= -9 -3

                                         2   -10.
 
Which matrix is the result of  a+b-c?

Answer 1

First compute a + b:
a + b = [(-5)+(-3) 1+5
7+1 (-4)+(-6)]
= [-8 6
8 -10]

Now subtract c:
(a + b) - c = [-8-(-9) 6-(-3)
8-2 -10-(-10)]
= [1 9
6 0]

So a + b - c = [[1, 9], [6, 0]].