Question 2451
 span(u,v,w) means the linear combinations of the three vectors u,v &w.

 Hence,  span(u,v,w) = {au+bv+cw| where a,b,c are scalars}

 Since u = 1* u  + 0*v + 0*w,
       v = 0* u  + 1*v + 0*w,
 and   w = 0* u  + 0*v + 1*w,
 we conclude that u,v and w belongs to span(u,v,w).

 This question is pretty basic so you have to work hard.

 Kenny