Can someone show me the steps to do this question:

Question

6x(r+s) - 12y(r+s)

Answer: 6(r+s)(x-2y)

Answer 1

r+s is common.
6 is common to 6 and 12.
Therefore 6(r+s) can be removed from both terms. What is left?
x in the first term and 2y in the second terms. SO
6(r+s)(x-2y)

Answer 2

Thanks, I understand now, I feel dumb now >_>

Answer 3

Plz show steps to this equation
z^6-64

answer: (z+2)(z-2)(z^4+4z^2+16)