Answer with Step-by-step explanation:
The given differential equation is

Now the above differential equation can be re-written as

Checking for exactness we should have



As we see that the 2 values are equal thus we conclude that the given differential equation is exact
The solution of exact differential equation is given by

The value of
can be obtained by differentiating u(x,y) partially with respect to 'y' and equating the result with P(x,y)

Sorry for my bad handwriting a notebook lol
The hourly rate is 60, so multiply 60 by the number of hours (h) and add the fee:
Answer: 60h + 35
Minimum point of an absolute value function is when f(x) = 0
0 = <span>|2x - 1|
2x</span> - 1 = 0
2x = 1
x = 1/2
Minimum point is (1/2, 0)
The correct answer is the last one.
Hope this helps :)