If A=3i+2j and B=j+2k then find A+B and A-B

You simply have to sum corresponding coordinates with each other.

Vector A is (3,2,0), meaning that its i-coordinate is 3, its j-coordinate is 2, and it has no k coordinate (it's zero).

Similarly, vector B is (0,1,2), meaning that its i-coordinate is 0, its j-coordinate is 1, and its k-coordinate is 2.

So, the sum of the i-coordinates is 3+0=3

The sum of the j-coordinates is 2+1=3

The sum of the k-coordinates is 0+2=2

So, the sum vector is A+B = (3,3,2) = 3i+3j+2k.

For A-B, you can work in the exact same way, but you'll subtract the coordinates instead of adding them.