Question

11．方程組$\left\{\begin{array}{l}x+y=5\\ 3x-y=3\end{array}\right.$的解是$\left\{\begin{array}{l}{x=2}\\{y=3}\end{array}\right.$．

Answer 1

分析 方程組利用加減消元法求出解即可．

解答 解：$\left\{\begin{array}{l}{x+y=5①}\\{3x-y=3②}\end{array}\right.$，
①+②得：4x=8，
解得：x=2，
把x=2代入①得：y=3，
則方程組的解為$\left\{\begin{array}{l}x=2\\ y=3\end{array}\right.$，
故答案為：$\left\{\begin{array}{l}{x=2}\\{y=3}\end{array}\right.$

點評 此題考查了解二元一次方程組，利用了消元的思想，消元的方法有：代入消元法與加減消元法．