Question

19．二元一次方程3x+2y=15的正整數(shù)解為$\left\{\begin{array}{l}{x=1}\\{y=6}\end{array}\right.$、$\left\{\begin{array}{l}{x=3}\\{y=3}\end{array}\right.$．

Answer 1

分析 將x看做已知數(shù)求出y，即可確定出正整數(shù)解．

解答 解：方程3x+2y=15變形，得：y=$\frac{15-3x}{2}$，
當(dāng)x=1時，y=6；當(dāng)x=3時，y=3；
∴方程3x+2y=15的正整數(shù)解為：$\left\{\begin{array}{l}{x=1}\\{y=6}\end{array}\right.$、$\left\{\begin{array}{l}{x=3}\\{y=3}\end{array}\right.$，
故答案為：$\left\{\begin{array}{l}{x=1}\\{y=6}\end{array}\right.$、$\left\{\begin{array}{l}{x=3}\\{y=3}\end{array}\right.$．

點評 此題考查了解二元一次方程，解題的關(guān)鍵是將x看做已知數(shù)求出y．