Derivative of ln(4x+25)

1. Let $u = 4 x + 25$.

2. The derivative of $\log{\left(u \right)}$ is $\frac{1}{u}$.

3. Then, apply the chain rule. Multiply by $\frac{d}{d x} \left(4 x + 25\right)$:

   1. Differentiate $4 x + 25$ term by term:

      1. The derivative of a constant times a function is the constant times the derivative of the function.

         1. Apply the power rule: $x$ goes to $1$

         So, the result is: $4$

      2. The derivative of the constant $25$ is zero.

      The result is: $4$

   The result of the chain rule is:

   $$\frac{4}{4 x + 25}$$

4. Now simplify:

   $$\frac{4}{4 x + 25}$$

The answer is:

$$\frac{4}{4 x + 25}$$