To make the sum of the vectors, we must make the sum of each of its components. Note that each comma indicates a different component and that component must be the same as that added to the other vector. If there is a number multiplying the vector, we will first proceed to perform the internal multiplication and then the sum.
A)
[tex]A+B = (2,-1,1)+(3,0,5)[/tex]
[tex]A+B = (5,-1,6)[/tex]
B)
[tex]B+C = (3,0,5)+(1,4,-2)[/tex]
[tex]B+C = (4,4,3)[/tex]
C)
[tex]A+B+C =(2,-1,1)+(3,0,5)+(1,4,-2)[/tex]
[tex]A+B+C = (6,3,4)[/tex]
D)
[tex]3A+2C = 3(2,-1,1)+2(1,4,-2)[/tex]
[tex]3A+2C = (8,5,-1)[/tex]
E)
[tex]2A+3B+C = 2(2,-1,1)+3(3,0,5)+)+(1,4,-2)[/tex]
[tex]2A+3B+C = (14,2,15)[/tex]
F)
[tex]2A+3(B+C) = 2(2,-1,1)+3((3,0,5)+(1,4-2))[/tex]
[tex]2A+3(B+C) = (16,10,11)[/tex]