differentiate

y = (x + 2) / (x^3 + x - 2)

Use the quotient law where you find the derivative of f(x)*g(x)-the derivative of g(x)*f(x) and the whole thing divided by g(x).

(x+2)(x^3+x-2)' - (x+2)'(x^3+x-2)
----------------------------------
(x^3+x-2)^2

(x+2)(3x^2+1) - 1(x^3+x-2)
----------------------------------
(x^3+x-2)^2