**Lesson Steps**:

To start, combine the exponentials. 12^x * 12^4 = 12^(x+4) = 12^8. Now just compare the left and right side and notice a simpler problem: x+4=8. Subtract 4 from both sides and x=4.

**Answer**:

x = 4

**Grade**: 8

**Level**: Middle school

**Subject**: Math

**Topic**: Algebra