Derivative of 2x-x^4

1. Differentiate $- x^{4} + 2 x$ 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: $2$

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

      1. Apply the power rule: $x^{4}$ goes to $4 x^{3}$

      So, the result is: $- 4 x^{3}$

   The result is: $2 - 4 x^{3}$

The answer is:

$$2 - 4 x^{3}$$