Question

下列說法正確的是

1. A.
   多項(xiàng)式乘以單項(xiàng)式，積可以是多項(xiàng)式也可以是單項(xiàng)式
2. B.
   多項(xiàng)式乘以單項(xiàng)式，積的次數(shù)等于多項(xiàng)式的次數(shù)與單項(xiàng)式次數(shù)的積
3. C.
   多項(xiàng)式乘以單項(xiàng)式，積的系數(shù)是多項(xiàng)式系數(shù)與單項(xiàng)式系數(shù)的和
4. D.
   多項(xiàng)式乘以單項(xiàng)式，積的項(xiàng)數(shù)與多項(xiàng)式的項(xiàng)數(shù)相等

Answer 1

D
分析：根據(jù)單項(xiàng)式乘以多項(xiàng)式的有關(guān)知識作答．
解答：A、多項(xiàng)式乘以單項(xiàng)式，積一定是多項(xiàng)式，而不是單項(xiàng)式，故本選項(xiàng)錯誤；
B、多項(xiàng)式乘以單項(xiàng)式，積的次數(shù)等于多項(xiàng)式的次數(shù)與單項(xiàng)式次數(shù)的和，故本選項(xiàng)錯誤；
C、多項(xiàng)式乘以單項(xiàng)式，積的系數(shù)是多項(xiàng)式系數(shù)與單項(xiàng)式系數(shù)的積，故本選項(xiàng)錯誤；
D、正確．
故選D．
點(diǎn)評：本題實(shí)際上考查了單項(xiàng)式乘以多項(xiàng)式的法則：單項(xiàng)式與多項(xiàng)式相乘，就是根據(jù)分配律用單項(xiàng)式去乘多項(xiàng)式的每一項(xiàng)，再把所得的積相加．