can't use both of their hands 和. can use both their hands

can't use both of their hands 和. can use both their hands
can't use both of their hands
can use both their hands
这两个短语里面怎么both的用法不一样呢,可不可以都用both of 或都用both,或者解释一下both分别在这两个短语里的词性