Question

12．如果$\left\{\begin{array}{l}{x=1}\\{y=2}\end{array}\right.$是二元一次方程組$\left\{\begin{array}{l}{ax+by=1}\\{bx+ay=2}\end{array}\right.$的解，那么a，b的值是（　　）

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

Answer 1

分析 由題意，$\left\{\begin{array}{l}{a+2b=1}\\{b+2a=2}\end{array}\right.$，解方程組，求出a，b的值．

解答 解：由題意，$\left\{\begin{array}{l}{a+2b=1}\\{b+2a=2}\end{array}\right.$，∴a=1，b=0，
故選B．

點評 本題考查解方程組，考查學生的計算能力，比較基礎．