Mr. jones has all the students in his class line up. the 9th student in line ends up being exactly at the middle of the line. how many students are in mr. jones's class?

The 9th student is in the middle.
⇒ There are 8 students before him
⇒ There are 8 students behind him

Total number of students = 8 + 1 + 8  = 17

17

1. isolate the variable, in this case, d. subtract 35.5 on both sides of the equation.2. 52 subtracted by 35.5 is 16.53. therefore your answer would be d= 16.5this is the basics of pre algebra, isolating variable through adding, subtracting, multiplying, and dividing, if you have any other questions to ask just comment!