sin x cos x =0
<=> sin x = 0 or cos x =0
This means, the zeros of sin AND zeros of cos are solutions. Do you know what the zeros are? (you probably should know that)
Sin x (cos x - 1) = 0
<=> sin x = 0 OR cos(x) - 1 = 0
<=> sin x = 0 OR cos(x) = 1
Do you know, where cos(x) = 1? You probably should know that too.
cos(0°) = 1 e.g. But there are some more solutions on [0°,360°]
Does it help?