PLEASE HELP ME WITH this question I need help a number one through four could you also explain how you got the answer thank you the person with the best answer will get BRAINLY !!!!!!!20 POINTS

Answer:
1. (c-d)(c+d)
2. (2c-3d(2c+3d)
3. (4ab-5cd)(4ab+5cd)
4. cannot be factorised into difference of two squares