Answer
$\approx 12.2$; $\approx 16.8$
and $\approx 23.25$
Work Step by Step
The rate of change in the x-direction is given as:
$f_x(3,2)=\dfrac{22.4-10.2}{3.5-2.5} \approx 12.2$
and
$f_x(3,2.2)=\dfrac{26.1-9.3}{3.5-2.5} \approx 16.8$
Also,
$f_{xy}(3,2)=\dfrac{(26.1-9.3)-(20.0-12.5)}{2.2-1.8} \approx 23.25$
