hello boys
I need some help with a few calculus problems
please message me if you can help
much love

what do you need?

I can't seem to find f'' of x^3 + y^3 = 126

I get f' to be -x^2/y^2 and then from there I'm lost

using quotient rule to find the second derivative

=[(-2x)y^2 - [(-x^2)2y*y']] / y^4

now sub in for y' = -x^2/y^2

[(-2x)y^2 - [(-x^2)2y*(-x^2/y^2)]] / y^4

and you can simplify as needed