Question

8．下列是二元一次方程組$\left\{\begin{array}{l}{x-y=1}\\{2x+y=2}\end{array}\right.$的解的是（　�。�

• A． $\left\{\begin{array}{l}{x=2}\\{y=1}\end{array}\right.$
• B． $\left\{\begin{array}{l}{x=0}\\{y=2}\end{array}\right.$
• C． $\left\{\begin{array}{l}{x=2}\\{y=-2}\end{array}\right.$
• D． $\left\{\begin{array}{l}{x=1}\\{y=0}\end{array}\right.$

Answer 1

分析 利用加減消元法求出方程組的解，即可作出判斷．

解答 解：$\left\{\begin{array}{l}{x-y=1①}\\{2x+y=2②}\end{array}\right.$，
①+②得：3x=3，
解得：x=1，
把x=1代入①得：y=0，
則方程組的解為$\left\{\begin{array}{l}{x=1}\\{y=0}\end{array}\right.$，
故選D

點評 此題考查了二元一次方程組的解，方程組的解即為能使方程組中兩方程都成立的未知數(shù)的值．