Question

單項(xiàng)式的系數(shù)是________，次數(shù)是________，多項(xiàng)式2-xy²-4x³y是________次多項(xiàng)式．

Answer 1

-    4    四
分析：?jiǎn)雾?xiàng)式的系數(shù)為除去未知量的常數(shù)，次數(shù)為未知量次數(shù)的總和．將多項(xiàng)式分解成若干個(gè)單項(xiàng)式，其中次數(shù)最高的單項(xiàng)式的次數(shù)就為此多項(xiàng)式的次數(shù)．
解答：?jiǎn)雾?xiàng)式的次數(shù)為：，次數(shù)為1+3=4．多項(xiàng)式分為三個(gè)單項(xiàng)式：2，-，-4x³y，次數(shù)分別為：0，3，4．所以此多項(xiàng)式的次數(shù)為4．
點(diǎn)評(píng)：本題重點(diǎn)是求解多項(xiàng)式的系數(shù)和次數(shù)．單項(xiàng)式的系數(shù)：?jiǎn)雾?xiàng)式中的數(shù)字因數(shù)及性質(zhì)符號(hào)叫做單項(xiàng)式的系數(shù)．單項(xiàng)式的次數(shù)：一個(gè)單項(xiàng)式中，所有字母的指數(shù)的和叫做這個(gè)單項(xiàng)式的次數(shù)．將多項(xiàng)式分解成若干個(gè)單項(xiàng)式，單項(xiàng)式的個(gè)數(shù)就為多項(xiàng)式的項(xiàng)說，單項(xiàng)式中次數(shù)最高一項(xiàng)的次數(shù)就為多項(xiàng)式的次數(shù)．