同类项是整式的重要内容之一,复习中,建议同学们能够切实理解和掌握以下五点. 一、掌握同类项的判定准则判定几个单项式是不是同类项,关键是“一看”“再看”,一看所含字母是否相同,再看相同字母的指数是否也相同.如3ax2y与5ax2y,所含字母都是a、x、y,且a的指数都是1,x的指数都是2,y的指数都是1,具备了“两相同”,所以它们是同类项;又如3ax2y与3axy2,虽然所含字母相 The same category is one of the important contents of the whole formula. During the review, it is suggested that the students can effectively understand and master the following five points. First, to determine the criteria of the same category to determine whether several single items are the same type of items, the key is “a look” and “re Look, if you look at the same letter, whether the index of the same letter is the same. If 3ax2y and 5ax2y, the letters are a, x, y, and the index of a is 1, the index of x is 2. The index of y is 1 and they have ”two identicals", so they are the same type of items; also 3ax2y and 3axy2, although they contain letters