I have next week an exam and I don't know how to solve the following 2 equations. If anyone knows how to solve them, please, help me.

sin2(4x) – sin2(2x) = 0

cos(2x) = cos(x) – sin(x)

The teacher gave me the solutions but I don't know how to get them. Here are the solutions:

http://img442.imageshack.us/img442/6461/67701671.png