**Remember the difference of two squares?**

**We can factor this guy:**

**You've probably been told that you couldn't factor this guy...**

**The SUM of two squares.**

**Well, they fibbed... You CAN factor this guy... Just not with real numbers.**

**We just need one more thing though:**

| |

**Squaring both sides gives**

**So, check this out:**

**I claim that**

**Just like the difference of two squares... but with i's after the numbers.**