Question

third derivative of y= x / 2x-1

Answer 1

I get -6/(2x-1)^4 but I am not sure if I am right

Answer 2

use the quotient rule:
u'v-uv'/ v^2

1(2x-1)-x(2) / (2x-1)^2

-1/(4x^2-4x+1)

Answer 3

then repeat the rule again to get
-(8x-4)/ (4x^2-4x+1)^2