NES Elementary Education Subtest 2 Practice Exam

In the expression 3x + 7, constants are the values that do not change, which means they do not contain any variables. In this case, the number 7 is a constant because it remains fixed regardless of the value assigned to the variable x. The coefficient 3, multiplying the variable x, is not considered a constant on its own because it changes based on the context of the variable it is associated with. Therefore, while 3 is part of the expression, it does not qualify as a constant in the same way 7 does.

Thus, confirming that the constants in the expression are represented by the number 7 alone, highlighting its fixed nature in comparison to the variable x and its coefficient.