Question

20．單項(xiàng)式-$\frac{{2}^{2}x{y}^{2}}{5}$ 的次數(shù)是（　�。�

• A． 3
• B． 4
• C． 5
• D． 6

Answer 1

分析 由于單項(xiàng)式的次數(shù)是其所含字母的指數(shù)和，由此即可求出單項(xiàng)式-xy²的次數(shù)．

解答 解：?jiǎn)雾?xiàng)式-$\frac{{2}^{2}x{y}^{2}}{5}$ 的次數(shù)是3，
故選A．

點(diǎn)評(píng) 此題主要考查了單項(xiàng)式的次數(shù)的定義，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．分別找出單項(xiàng)式的系數(shù)和次數(shù)的規(guī)律也是解決此類問(wèn)題的關(guān)鍵．