Oo, I remember this module well!
Synergy is all about using one oil with another to enhance properties.
Make sure that you give reference to the oils choices reflecting your mind body spirit considerations.
Treat the whole person and not just the condition.
Carrier oils do have similar properties but to a lesser degree.
You could use rose oil with borag oil and evening primrose for example for a woman that is depressed about menopause. Each of these would address the depression and the hormones.
For example using sea buckthorn or St Johns Wort with Juniper to help cleanse the joints in arthritis. Both do the job, in varying ways. The carrier oils are not so potent but blending them raises the vibration exponentionally. Another example would be calendula carrier and essential oil for eczema. Likewise Borage or evening primrose C/Os
The obvious choice would be to blend for massage but a synergistic blend can be carried across into any carrier so you could use a few drops in a cream or ointment for example. In actual fact there would be nothing to stop you also integrating flower essences to really charge the blend too.
Blending is also about getting your notes right. Have a look on my site on the page about perfume blending, and there is details about top middle and base notes,
Let me know if you get stuck any more...