4. [2 points each] (a) Write W1 2 (1,0), W2 : (0,1), and W3 2 (11,6) as linear combinations of v1 2 (5,4) and v2 : (2,3). (b) Let v1 = (2,1,5), v2 = (0,1,4), v3 = (2,4,17). What is span(v1,v2,v3)? Could it be all of R3