If there is such a scalar function <em>f</em>, then



Integrate both sides of the first equation with respect to <em>x</em> :

Differentiate both sides with respect to <em>y</em> :


Integrate both sides with respect to <em>y</em> :

Plug this into the equation above with <em>f</em> , then differentiate both sides with respect to <em>z</em> :



Integrate both sides with respect to <em>z</em> :

So we end up with

Answer:
19
Step-by-step explanation:
See the attached files
<h2>Explanation:</h2>
Here we have the following inequality:

In order to graph the shaded region, we have to graph the equation of the line
whose slope is
and y-intercept
. So the graph of the line is shown in the First Figure below.
To find the shaded region we need to have a look at the symbol > that indicates that the shaded region is above the graph of the line and. Since this doesn't include the symbol =, then the line is dotted. Therefore, the resulting region is shown in the second Figure.
<h2>Learn more:</h2>
Shaded regions: brainly.com/question/9611462
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The second one is the answer
The equation to find Amy's earning after tutoring for 15 hours is 300 dollars.
<h3>How to find an equation?</h3>
She earn 20 dollars for each hours she tutors.
E = earnings in dollars
H = hours of tutoring
The equation relating E and H are as follows:
E = 20H
Therefore, the equation to find Amy's earning after tutoring for 15 hours is as follows;
E = 20H
E = 20 × 15
E = 300 dollars
Therefore, Amy's tutoring for 15 hours is 300 dollars.
learn more on expression here: brainly.com/question/14492671
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