Determine the dimensions of the following subspaces of R^2 and R^3?

1. R^3= span{(-2, -12, 10), (-1, 3, -4), (2, 3, -1)}

2. R^2= span{(–4, –2), (2, 0), (5, 0), (9, –1), (–2, 3)}

3. R^2= span{(7, –2), (–6, 5)}

4. R^2= span{(0, 0)}

5. R^3= span{(–20, –4, 8), (–1, –4, –2), (10, 2, –4), (–4, 3, 4)}

6. R^2= span{(–5, –7), (–6, 7, –8), (4, 8, –2)}

How would I go about doing this problem?