Sections 1.5 and 1.7 are challenging for many peopleSome problems are more effective if you do all the problems in the block; for example, I would really like to have assigned all of problems 16–27 in Section 1.7. A big family of examples like that will give you a better handle on how linearly independent (or dependent) sets of vectors behave. So, my suggestion is to do as many problems as you can from the blocks 13–20 and 42–49 in Section 1.5; 7–12 in Section 1.6; and 1–14 and 16–27 in Section 1.7. The more of these you can do, the more examples you'll have seen of ideas like linear combination, linear independence, and linear dependence.