The answer is A (6) because 41+22+9=72, and there are 72 students enrolled in either of the courses. When you subtract 72 from 78 you get 6, which is the ending amount of students hat are not enrolled in French class, or German class.
96=(x+8)*x*(x-2)=x^3 +6x^2 -16x. Solve to get x= -6,-4,4. Negative distance doesn't make sense, so x=+4. Therefore, length is (x+8)=(4+8)= 12, width=x=4, and height=(x-2)=(4-2)=2.
