Question

17．二元一次方程组$\left\{\begin{array}{l}{x+y=6}\\{x-3y=-2}\end{array}\right.$的解是（　　）

• A． $\left\{\begin{array}{l}{x=5}\\{y=1}\end{array}\right.$
• B． $\left\{\begin{array}{l}{x=4}\\{y=2}\end{array}\right.$
• C． $\left\{\begin{array}{l}{x=-5}\\{y=-1}\end{array}\right.$
• D． $\left\{\begin{array}{l}{x=-4}\\{y=-2}\end{array}\right.$

Answer 1

分析 用加减消元法解方程组即可．

解答 解：①-②得到y=2，把y=2代入①得到x=4，
∴$\left\{\begin{array}{l}{x=4}\\{y=2}\end{array}\right.$，
故选B．

点评 本题考查解二元一次方程组，解题的关键是熟练掌握加减消元法或代入消元法解方程组，属于中考常考题型．