Question

5．下列方程組中，屬于三元一次方程組的是（　�。�

• A． $\left\{\begin{array}{l}{2x+y-z=2}\\{x-y+z=-5}\\{y：z=3}\end{array}\right.$
• B． $\left\{\begin{array}{l}{x+y=-3}\\{y-z=4}\\{w+z=5}\end{array}\right.$
• C． $\left\{\begin{array}{l}{\frac{x}{2}+y=7}\\{3x+\frac{y}{3}-z=3}\\{2x-y+z=5}\end{array}\right.$
• D． $\left\{\begin{array}{l}{2y-z=-2}\\{x+2y=5}\\{\frac{2}{y}=-1}\end{array}\right.$

Answer 1

分析 利用三元一次方程組的定義判斷即可．

解答 解：屬于三元一次方程組的是$\left\{\begin{array}{l}{\frac{x}{2}+y=7}\\{3x+\frac{y}{3}-z=3}\\{2x-y+z=5}\end{array}\right.$，
故選C

點(diǎn)評(píng) 此題考查了解三元一次方程組，熟練掌握三元一次方程組的定義是解本題的關(guān)鍵．