Derivative of (5*x-9)^2

1. Let $u = 5 x - 9$.

2. Apply the power rule: $u^{2}$ goes to $2 u$

3. Then, apply the chain rule. Multiply by $\frac{d}{d x} \left(5 x - 9\right)$:

   1. Differentiate $5 x - 9$ 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: $5$

      2. The derivative of the constant $-9$ is zero.

      The result is: $5$

   The result of the chain rule is:

   $$50 x - 90$$

The answer is:

$$50 x - 90$$