An equation has an = sign

2 + 3 = 5

3x + 2 = 8

4x = 8

x/5 = 3

9x − 4
*
Not an equation as it does not have = sign
*

20x + 3 = 0

3x – 5 < 0
*
Not an equation as it does not have = sign
*

Here,

2 + 3 = 5 is an equation

But it does not have a variable.

So, It is an equation without variables,

But here,

We will study equations with variables