Final answer:
The question asks to find the value of variables in an expression, but there is not enough information provided. Linear equations were discussed in Practice Test 4, yet the provided expression doesn't seem to be a linear equation, and it's not covered in the provided test material.
Step-by-step explanation:
The question provided is asking for the value of each variable in a mathematical expression, but the information given is insufficient for a direct calculation. However, if this relates to Practice Test 4, and the chapter on Linear Equations, we can discuss what constitutes a linear equation and how to identify them.
A linear equation is of the form y = mx + b, where m is the slope of the line and b is the y-intercept. In the context of Practice Test 4's solutions, it's noted that options A, B, and C are all linear equations.
To address the specific example, if we follow Practice Test 4 Solutions format, and if the given expression (x + 12)°/y refers to dividing an angle measured in degrees by some unknown y, there's not enough context to find values for x or y directly. More information would be needed to solve for these variables.