Might or might not work, not all DRAM will play together with other sticks. Even mixing sticks of the same exact model from different packages can be problematic - that's why they make DRAM and sell it in a wide variety of packaging different numbers of sticks and different amounts, the forums are full of questions like 'added 4GB and now my computer won't boot'
If you're asking, 'will my machine still run if I do this?' then yes, it should. However, those sticks will not run in dual-channel and will run at the slower of the two settings, so CL10 in your case.
Might or might not work, not all DRAM will play together with other sticks. Even mixing sticks of the same exact model from different packages can be problematic - that's why they make DRAM and sell it in a wide variety of packaging different numbers of sticks and different amounts, the forums are full of questions like 'added 4GB and now my computer won't boot'