Final answer:
The expression 'x-3' means 'subtract 3 from a number,' where x represents an unknown or variable number. If x is positive, subtracting 3 yields a smaller number; if x is negative, subtracting 3 yields a more negative value. The expression follows the rules for combining signs in arithmetic.
Step-by-step explanation:
The expression x-3 can be completed as 'subtract 3 from a number'. In mathematics, the variable x typically represents an unknown value that we are trying to determine or a value that can vary. When x is followed by -3, it means that we are taking the value represented by x and subtracting 3 from it.
For instance, if x is the number of children in a family, then subtracting 3 from this number would give us the number of children subtracted by 3. If x = 5, then x - 3 would be equal to 2, because 5 - 3 = 2.
Additionally, the sign of the numbers involved is crucial. If x is a positive number, then x - 3 will result in a number less than x. If x is a negative number, then subtracting 3 makes the value more negative. The rules for combining signs—such as multiplying or dividing numbers with the same or different signs—also apply when determining the sign of the final answer in expressions like x - 3.