Determine d2y
----- for y=3x+2
dx^2 ------
5x-8

Here's a link that explains what differentiation is and how to do it.

Differentiation (Finding Derivatives) (http://www.intmath.com/Differentiation/Differentiation-intro.php)

In particular, this link shows how to differentiate polynomials:

5. Derivatives of Polynomials (http://www.intmath.com/Differentiation/5_Derivative-polynomials.php)

Your post is a little discombobulated. I assume you want to find the second derivative of

y=\frac{3x+2}{5x-8}

We can try the quotient rule.

\frac{g(x)f'(x)-f(x)g'(x)}{[g(x)]^{2}}

\frac{(5x-8)(3)-(3x+2)(5)}{(5x-8)^{2}}=\frac{-34}{(5x-8)^{2}}

Now, find the derivative of that and you have it.

You could even use the product rule by rewriting as -34(5x-8)^{-2}

May be a little easier.