Final answer:
The expressions 4x+23 and 10x-1 are variable expressions because they contain the variable x, whose value can change. The number 78 is a constant because it does not contain any variables and thus has a fixed value.
Step-by-step explanation:
The student's question appears to be asking how to categorize each of the provided expressions. To answer this, we need to determine if each expression is a variable expression or a constant.
- 4x+23: This is a variable expression because it contains a variable, x, which means its value can change depending on the value of x.
- 10x-1: Similarly, this is also a variable expression as it includes the variable x.
- 78: This is a constant because it does not contain any variables and its value is fixed.
- 78: As with the previous 78, this is also a constant for the same reason—it does not contain variables.
Therefore, the correct answer is:
4x+23: Variable expression; 10x-1: Variable expression; 78: Constant; 78: Constant
All of the options A, B, C, and D given by the student are identical and correct.