Can I upgrade my laptop's RAM from 16GB to 48GB by adding a 32GB stick?

Probably, but check your laptop’s specs first. Most laptops with soldered RAM have one empty SODIMM slot, and you can usually add a 32GB stick for 48GB total. However, some laptops cap RAM per slot at 16GB or 32GB, so look up your exact model. Mixing capacities loses full dual-channel performance, but for most tasks you won’t notice, and it’s still a massive upgrade for memory-intensive work.