Answer
A+2B=(16 -10 1 \ 8 -5 0)
3C-E is undefined.
CB=(9 -13 -5 \ -13 6 -5)
EB is undefined.
Work Step by Step
A+2B=(2 0 -1 \ 4 -5 2)+2(7 -5 1 \ 1 -4 -3)=(2 0 -1 \ 4 -5 2)+(14 -10 2 \ 4 0 -2)=(16 -10 1 \ 8 -5 0)
3C-E is undefined, because the matrices are not of the same size. C=2x2, and E=2x1.
CB=(1 2 \ -2 1)(7 -5 1 \ 1 -4 -3)=(7+2 -5-8 1-6 \ -14+1 10-4 -2-3)=(9 -13 -5 \ -13 6 -5)
E has 1 column, but B has 2 rows. Thus, EB is undefined.