Answer:
-3
Step-by-step explanation:
The number line is the straight line where all the numbers are expressed and when we represent this line we usually use intervals of the same length to express the numbers. For example, the numbers 0, 1, 2, 3, 4 would have the same distance between them since there is one integer between each of them.
The number line also has negative numbers, so the integer to the left of the zero is -1, then we have -2, -3, etc.
In this example we are told that the integer 3 is 3 units from 0 on the number line, this number is 3 units from zero to the right (positive numbers). So, as we said before, if we move 3 units from 0 but to the left we would be 3 units from 0 but on the side of negative numbers and thus, the integer that is also 3 units from zero on the number line is -3.