\(\displaystyle 3x-1=5\)
\(\displaystyle xy=1\)
\(\displaystyle x-\frac{1}{y}=6\)
\(\displaystyle \frac{1}{5}\left( {x+y} \right)=7\)
\(\displaystyle x-{{y}^{2}}=0\)
是二元一次方程的个数有( 1 )个?
\(\displaystyle 3x-1=5\)是一元一次方程;
\(\displaystyle xy=1\)和\(\displaystyle x-{{y}^{2}}=0\)是二元二次方程;
\(\displaystyle x-\frac{1}{y}=6\)是分式方程;
\(\displaystyle \frac{1}{5}\left( {x+y} \right)=7\)是二元一次方程;
二元二未知,次数一最高,整式是前提,系数不为0
