Differentiate implicitly to find dx
dy
​
. x 2
−9xy+y 2
−6x+y−6=0 dx
dy
​
= 2y+9x+1
2x+9y−6
​
dx
dy
​
= 2y+9x+1
2x+9y+6
​
dx
dy
​
=− 2y+9x+1
2x+9y+6
​
dx
dy
​
=− 2y−9x+1
2x−9y−6
​
dx
dy
​
= 2y−9x−1
2x−9y−6
​