Question

19．二元一次方程3x+2y=15的正整数解为$\left\{\begin{array}{l}{x=1}\\{y=6}\end{array}\right.$、$\left\{\begin{array}{l}{x=3}\\{y=3}\end{array}\right.$．

Answer 1

分析 将x看做已知数求出y，即可确定出正整数解．

解答 解：方程3x+2y=15变形，得：y=$\frac{15-3x}{2}$，
当x=1时，y=6；当x=3时，y=3；
∴方程3x+2y=15的正整数解为：$\left\{\begin{array}{l}{x=1}\\{y=6}\end{array}\right.$、$\left\{\begin{array}{l}{x=3}\\{y=3}\end{array}\right.$，
故答案为：$\left\{\begin{array}{l}{x=1}\\{y=6}\end{array}\right.$、$\left\{\begin{array}{l}{x=3}\\{y=3}\end{array}\right.$．

点评 此题考查了解二元一次方程，解题的关键是将x看做已知数求出y．