[Implicit Differentiation]

Question

(6+y)^3 + 4y = x + 55 with y' at (1, -2)

y' at (1,-2) =?

I got this far but I'm not sure if I'm doing it right: 3(6+y)^2(1dy/dx)+4dy/dx=1

Answer 1

good so far, now sub in the point

3(6-2)^2(dy/dx) + 4dy/dx = 1
148dy/dx = 1
dy/dx = 1/144

Answer 2

Not correct.

Answer 3

then surely you can find my arithmetic error, I just noticed it too.