Question

18．若-63a³b⁴與81a^x+1b^x+y是同類項，則x、y的值為（　�。�

• A． $\left\{\begin{array}{l}{x=1}\\{y=3}\end{array}\right.$
• B． $\left\{\begin{array}{l}{x=2}\\{y=-2}\end{array}\right.$
• C． $\left\{\begin{array}{l}{x=1}\\{y=2}\end{array}\right.$
• D． $\left\{\begin{array}{l}{x=2}\\{y=2}\end{array}\right.$

Answer 1

分析 根據(jù)同類項的定義進行選擇即可．

解答 解：∵-63a³b⁴與81a^x+1b^x+y是同類項，
∴x+1=3，x+y=4，
∴x=2，y=2，
故選D．

點評 本題考查了同類項，掌握同類項的定義是解題的關(guān)鍵．