# Find the derivative of the function using the definition of the derivative: g(x) = 5 − x.

We will use the concept of derivative by the first principle and find the derivative.

## Answer: g^{'}(x) = -1

Let us see how we will use the concept of derivative by the first principle and find the derivative.

**Explanation**:

Derivative by the first principle is stated as

f^{'}(x) = [f (x + h) + f (x)] / h where h << 0

Hence, let us find derivative for g(x)

g^{'}(x) = [5 - (x + h) - 5 + x] / h

g^{'}(x) = -h / h