Question

20．方程组$\left\{\begin{array}{l}4x-3y=k\\ 2x+3y=5\end{array}\right.$的解与x与y的值相等，则k等于（　　）

• A． 1
• B． 2
• C． 3
• D． 4

Answer 1

分析 将y=x代入方程组$\left\{\begin{array}{l}4x-3y=k\\ 2x+3y=5\end{array}\right.$，得$\left\{\begin{array}{l}{x=k}\\{5x=5}\end{array}\right.$，解此方程组即可求出k的值．

解答 解：将y=x代入方程组$\left\{\begin{array}{l}4x-3y=k\\ 2x+3y=5\end{array}\right.$，得$\left\{\begin{array}{l}{x=k}\\{5x=5}\end{array}\right.$，
解得：$\left\{\begin{array}{l}{x=1}\\{k=1}\end{array}\right.$，
故选：A．

点评 本题考查的是解二元一次方程组，解决本题的关键是解二元一次方程组．