I've been trying to figure out complex numbers as vectors but the book is hard to understand. Can someone please help me out on these problems, my homeworks due in 4 hours.

1.Show which of the following subsets R^3 are subspaces and which are not:

a.The set of vectors in R^3 with first component 1;

b.All vectors x3=0;

c.The set of vectors with nonzero first component.

2.Polar form of complex number:

Write the complex number z=sqrt(3) + i in polar form and find its magnitude and angle in the complex plane.

3.Compute z/zbar where z=3-4i