Answer:

Step-by-step explanation:
Consider the given differential equation is



Taking all variables on right sides.


Let as assume,
and 
Find partial derivatives
and 
and 
Since
, therefore the given differential equation is exact.
The solution of the exact differential equation is






Given:
The sequence is 25, 20, 15, 10, 5.
To find:
The ninth term of the given sequence.
Solution:
We have,
25, 20, 15, 10, 5
It is an AP because the difference between two consecutive terms are same.
Here,
First term (a) = 25
Common difference (d) = 20-25
= -5
The nth terms of an AP is

Where, a is the first term and d is the common difference.
Putting a=25, n=9 and d=-5 to get the 9th term.




Therefore, the ninth term of the given sequence is -15.
Answer:
Step-by-step explanation:
.
Answer:
9 x + 42.
Step-by-step explanation: