Please help!! Geometry, will mark brainliest!

n = 36

Step-by-step explanation:

The opposite sides of a parallelogram are congruent , that is

AB = DC , substitute values

n - 5 = n + 7 ( multiply through by 3 to clear the fractions )

2n - 15 = n + 21 ( subtract n from both sides )

n - 15 = 21 ( add 15 to both sides )

n = 36

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.