Take a look at this if you're good at calculus PLEASE?

Question

Take a look at this and tell me where I'm going wrong.
Find dy/dx
cos(x-y)=-12sin(xy)
-sin(x-y)(-dy/dx)=-12cos(xy)(y+x(dy/dx))
dy/dx=-12ycos(xy)/(sin(x-y)+x)

I think I'm screwing up when distributing factors after the product rule. Anyways, if anyone knows what to do please let me know!
THANKS GUYS!!! :)

Oops! I guess it cut off the second line a little. It should continue...+x(dy/dx)

Answer 1

d/dx[cos(x-y)] = (1-dy/dx)*-sin(x-y)

d/dx[-12sin(xy)] = -12cos(xy)[x*dy/dx + y]

(-1+dy/dx)sin(x-y) = -12cos(xy)[x*dy/dx + y]

-sin(x-y) +(dy/dx) sin(x-y) = -12cos(xy) x*(dy/dx) - 12ycos(xy)
[12cos(xy)+sin(x-y)]dy/dx = sin(x-y) - 12ycos(xy)

dy/dx = [sin(x-y) - 12cos(xy)]/[12cos(xy) + sin(x-y)]

Answer 2

cos(x-y)=-12sin(xy)
Take derivative d/dx
-sin(x-y)(1-dy/dx)=-12cos(xy)(y+xdy/dx)
Now solve for dy/dx