# Differential Equations and Their Solutions Exercises

### Example 1

Determine if the equation is a differential equation.

f (2)(x) + f (x) = 7x

### Example 2

Determine if the equation is a differential equation.

### Example 3

Determine if the equation is a differential equation.

x2 + f 2(x) = 0

### Example 4

Determine if the equation is a differential equation.

x2 + y2 = 4xy

### Example 5

Determine if the equation is a differential equation.

### Example 6

Determine if the equation is a differential equation.

y + y2 + y3 = x

### Example 7

Determine if the equation is a differential equation.

### Example 8

Determine if the equation is a differential equation.

y' + 2y'' = 3 – x

### Example 9

Determine the order of the differential equation.

### Example 10

Determine the order of the differential equation.

y" + y' – y = 0

### Example 11

Determine the order of the differential equation.

f '(x) = x2 + 3x + 5

### Example 12

Determine the order of the differential equation.

f (x) – f 3(x) + f (2) = 7x

### Example 13

Determine the order of the differential equation.