Factor each polynomial.
1. 12qg² - 169h⁴
2. 25+² - 36+⁴
3. 144r² - 49s²
4. 20w⁴ - 405x⁶
5. 16 + 24t + at²
6. 25y² + 7oyz + 49z²
7. 4g² - 4ģ + 1
8. 4 - 36u + 81u²​