Question

12．若方程组$\left\{\begin{array}{l}{2a-3b=13}\\{3a+5b=30}\end{array}\right.$的解是$\left\{\begin{array}{l}{a=8.3}\\{b=1.2}\end{array}\right.$，则方程组$\left\{\begin{array}{l}{2（x+2）-3（y-1）=13}\\{3（x+2）+5（y-1）=30}\end{array}\right.$的解是（　　）

• A． $\left\{\begin{array}{l}{x=8.3}\\{y=1.2}\end{array}\right.$
• B． $\left\{\begin{array}{l}{x=10.3}\\{y=1.2}\end{array}\right.$
• C． $\left\{\begin{array}{l}{x=6.3}\\{y=2.2}\end{array}\right.$
• D． $\left\{\begin{array}{l}{x=10.3}\\{y=0.2}\end{array}\right.$

Answer 1

分析 根据加减法，可得（x+2）、（y-1）的解，再根据解方程，可得答案．

解答 解：∵方程组$\left\{\begin{array}{l}{2a-3b=13}\\{3a+5b=30}\end{array}\right.$的解是$\left\{\begin{array}{l}{a=8.3}\\{b=1.2}\end{array}\right.$，
∴方程组$\left\{\begin{array}{l}{2（x+2）-3（y-1）=13}\\{3（x+2）+5（y-1）=30}\end{array}\right.$中$\left\{\begin{array}{l}{x+2=8.3}\\{y-1=1.2}\end{array}\right.$
∴$\left\{\begin{array}{l}{x=6.3}\\{y=2.2}\end{array}\right.$
故选：C．

点评 本题考查了二元一次方程组的解，解决本题的关键是先求（x+2）、（y-1）的解，再求x、y的值．