Question

18．下列各对数中，满足方程组$\left\{\begin{array}{l}{3x-y=6}\\{x+y=2}\end{array}\right.$的是（　　）

• A． $\left\{{\begin{array}{l}{x=2}\\{y=0}\end{array}}\right.$
• B． $\left\{{\begin{array}{l}{x=1}\\{y=1}\end{array}}\right.$
• C． $\left\{{\begin{array}{l}{x=-4}\\{y=6}\end{array}}\right.$
• D． $\left\{{\begin{array}{l}{x=3}\\{y=-1}\end{array}}\right.$

Answer 1

分析 方程组利用加减消元法求出解即可．

解答 解：$\left\{\begin{array}{l}{3x-y=6①}\\{x+y=2②}\end{array}\right.$，
①+②得：4x=8，即x=2，
把x=2代入②得：y=0，
则方程组的解为$\left\{\begin{array}{l}{x=2}\\{y=0}\end{array}\right.$．

点评 此题考查了解二元一次方程组，熟练掌握运算法则是解本题的关键．