The solution of (xy + y2)dx = (x2- xy)dy is
1
\(\rm \log x+ {2x\over y}-{1\over 2}\ {log{y\over x}} = c\)
2
\(\rm \log x+ {2x\over y}+{1\over 2}\ {log{y\over x}} = c\)
3
\(\rm \log x+ {x\over 2y}+{1\over 2}\ {log{y\over x}} = c\)
4
\(\rm \log x- {x\over 2y}+{1\over 2}\ {log{y\over x}} = c\)