I need help factoring (in R and in C) please...!?

I need help factoring the following please...

1. Factor completely (in R), if possible:

5x^2 - 625

2. Factor completely (in R), if possible:

5x^2 + 625

3. Factor completely (in C), if possible:

5x^2 + 625

4. Factor completely (in R), if possible:

5x^3 + 625

5. Factor completely (in C), if possible:

5x^3 + 625

6. Factor completely (in R), if possible:

5x^3 - 625

Thanks so much for your help! :<)