Question

Find the derivative of f(x) = 5x + 9 at x = 2.

Answer 1

If x=2 then\[f(2)=7+9=16\]The derivative of a constant is zero so,\[f'(2)=0\]

Answer 2

I meant:

\[f(2)=10+9=19\]\[f'(2)=0\]

Answer 3

Would you not find the derivative and then pass in 2 as x.
\[f(x)=5x+9\]
\[f \prime (x) = 5\]
Therefore, \[f \prime (2) = 5\]