Question

3．方程組$\left\{\begin{array}{l}{x=3}\\{2x-3y=9}\end{array}\right.$的解為$\left\{\begin{array}{l}{x=3}\\{y=0}\end{array}\right.$．

Answer 1

分析 把①代入②得出9-3y=9，求出y=0，即可求得方程組的解．

解答 解：$\left\{\begin{array}{l}{x=3①}\\{3x-3y=9②}\end{array}\right.$，
把①代入②得：9-3y=9，
-3y=0，
解得：y=0，
即原方程組得解為：$\left\{\begin{array}{l}{x=3}\\{y=0}\end{array}\right.$．
故答案為：$\left\{\begin{array}{l}{x=3}\\{y=0}\end{array}\right.$．

點(diǎn)評(píng) 本題考查了解二元一次方程組得應(yīng)用，關(guān)鍵是能把二元一次方程組轉(zhuǎn)化成一元一次方程．