0.144 because the number after 3 is 5 and that rounds the 3 to a 4.
A. correct as it is
B. 5, 4, 3, 0
I would say the answer would be
6+3u
THe problem is basically telling us: 
where P is the power disappated and V^2 is our voltage squared.

So, for the second example to find the power we simply have to plug k and our voltage back in, so: