i think the answer is c :)
Solution :
Group Before After
Mean 693.75 743.75
Sd 155.37 143.92
SEM 54.93 50.88
n 8 8
Null hypothesis : The preparation course not effective.

Alternative hypothesis : The preparation course is effective in improving the exam scores.
(after - before)
Answer:
9x(4+8y+3y)
Step-by-step explanation:
36x+72xy+27xy
9x(4+8y+3y)