Final answer:
The variable that equals 55 is likely (D) y, referring to the final exam history grades. Without more context or specific equations connecting the variables x or y to the number 55 directly, it's challenging to provide a definitive answer.
Step-by-step explanation:
To determine which variable equals 55 from the options given, we need to review the data provided in the various sections of the practice test referenced.
There is no direct information linking the variables x or y to the value 55 within the context of the provided math problems. However, we can examine the data related to final exam grades for math (x) and history (y), given in one segment of the provided test information. None of the listed x values equals 55, but the history grades (variable y) contain a grade of 55. Therefore, it is likely that the option which equals 55 is (D) y, assuming that we are referring to the history final exam grades.
However, without a specific equation or context directly correlating to the variables, it is difficult to provide a definitive answer. The information from Practice Test 4, section 12.1 Linear Equations and other sections do not provide a clear solution to the question posed.