find (a)2v+u, (b)u-3v), and (c)5u-v.

1.u=i-j, v=6i+9j
2.u=2i+3j, v=-i-2j

These are just multiply, group, and combine. For instance,

2a: 2v+u=2(i-2j)+(2i+3j)=2i+2i-4j+3j=4i-j