To differentiate: xey=y-1
Answer: y'=ey1-xey
Differentiating w.r.t x
ddxxey=ddxy-1
xddxey+ey.1=dydx
x.ey.y'+ey=y'
y'1-xey=ey
y'=ey1-xey
Formula used:
ddxuv=uv'-vu'
Conclusion: