Question

1．二元一次方程2x+y=5的正整數(shù)解為$\left\{\begin{array}{l}{x=1}\\{y=3}\end{array}\right.$，$\left\{\begin{array}{l}{x=2}\\{y=1}\end{array}\right.$．

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2x+y=5，
解得：y=-2x+5，
當x=1時，y=3；x=2時，y=1，
則方程的正整數(shù)解為$\left\{\begin{array}{l}{x=1}\\{y=3}\end{array}\right.$，$\left\{\begin{array}{l}{x=2}\\{y=1}\end{array}\right.$，
故答案為：$\left\{\begin{array}{l}{x=1}\\{y=3}\end{array}\right.$，$\left\{\begin{array}{l}{x=2}\\{y=1}\end{array}\right.$

點評 此題考查了解二元一次方程，熟練掌握運算法則是解本題的關(guān)鍵．