You're explanation for number one also works for numbers 2 and three. They just want you to understand that it can work with any number. So, for instance, number two states that (xyz)^4=x^4 * y^4 * z^4, and this is true because the fourth power is distributed between x, y and z. [(x*x*x*x)(y*y*y*y)(z*z*z*z)]
then 
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