Question

A differentiable function g has the values shown below. Estimate f'(2.5).

Answer 1

I assume you meant to say "a differentiable function f has the values ..." and not g.

Since f is differentiable, the mean value theorem holds, so you can approximate

f ' (2.5) ≈ (f (2.6) - f (2.4)) / (2.6 - 2.4) = (24 - 18) / (0.2) = 30