What is the units digit of 13^2012 ?
a.1
b.3
c.5
d.7
e.9

I'm confused on this could anyone me and show me what i need to do to solve it.

Will give a: 122 b: 90 c: 48 d: 180

Problem number 26 of the rhind papyrus says: find a quantity such that when it is added to of itself the result is a 15. the modern day equation that models this problem is x + x = 15. what is the solution to the equation? x = 10 x = 12 x = 15 x = 30