Final Answer:
a. The first-order partial derivative

b. The second-order partial derivative

c. The second-order partial derivative

Explanation:
Given the equation
defines z as a differentiable function of x and y around the point

To find the first-order partial derivative
we differentiate the equation with respect to z, holding x and y constant, which yields

For the second-order partial derivatives, we differentiate
twice. The second-order partial derivative
is calculated as
{25}\), and the second-order mixed partial derivative

The first-order partial derivative represents the rate of change of z with respect to changes in both x and y. The second-order partial derivatives show how this rate of change changes concerning z in a second order, allowing a deeper understanding of the behavior of z concerning x and y.
Understanding these derivatives aids in analyzing the behavior of the function z with respect to simultaneous changes in x and y, providing crucial information about the function's curvature and rates of change in the specified neighborhood.