# NCERT Class 12-Mathematics: Chapter – 9 Differential Equations Part 8 (For CBSE, ICSE, IAS, NET, NRA 2022)

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**Question 17**:

Find the general solution of the differential equation

**Answer**:

**Question 18**:

Find the general solution of .

**Answer**:

Given, differential equation is

Dividing both sides by

Which is a homogeneous differential equation

On substituting these value in Eq. (i) , we get

On integrating both sides, we get

**Question 19**:

Solve: . [**Hint**: Substitute after separating and

**Answer**:

**Question 20**:

Solve:

**Answer**:

**Question 21**:

Solve the differential equation *dx* given that when

**Answer**:

**Question 22**:

Form the differential equation by eliminating A and B in .

**Answer**:

**Question 23**:

Solve the differential equation .

**Answer**:

**Question 24**:

Find the differential equation of system of concentric circles with centre .

**Answer**:

On differentiating Eq. (i) , we get