Question

代數(shù)式3xy的次數(shù)是

1. A.
   1
2. B.
   2
3. C.
   3
4. D.
   -1

Answer 1

B
分析：根據(jù)單項(xiàng)式次數(shù)的定義來(lái)求解．單項(xiàng)式中數(shù)字因數(shù)叫做單項(xiàng)式的系數(shù)，所有字母的指數(shù)和叫做這個(gè)單項(xiàng)式的次數(shù)．
解答：根據(jù)單項(xiàng)式定義得：代數(shù)式3xy的次數(shù)是2．
故選B．
點(diǎn)評(píng)：本題主要考查單項(xiàng)式的次數(shù)：確定單項(xiàng)式的系數(shù)和次數(shù)時(shí)，把一個(gè)單項(xiàng)式分解成數(shù)字因數(shù)和字母因式的積，是找準(zhǔn)單項(xiàng)式的系數(shù)和次數(shù)的關(guān)鍵．