Were you planning to show any of your work or explain why you want someone else to do your exams for you?
I the ARoR is "i", then define v = 1/(1+i)
Then 10 = 0.5(v + v^2 + v^2) + 12v^3
Solve for i.
If you are struggling with thisone, there is not much point in trying the other two. Good luck, though.