What does "when x is an integer" mean?

x = whole-valued numbers without fractions or decimal.

Step-by-step explanation:

An integer in mathematics refers to a whole number that can either be a positive or negative number but without any fractional part. Integers are numbers such as -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5 etc.

Hence, when we say "x" is an integer, it simply means that the value of x should be a whole number that can either be a positive or negative number but without any fractional or decimal value or part.

In Mathematics, when solving for an unspecified or unknown integer we can use a lowercase alphabet "x" to denote the integer.

For instance;

2x + 5 = 11

2x = 11 - 5

2x = 6

Dividing both sides by 2, we have;

x = 3.