When was obama elected as the president of america?

answer; ///i do believe that the correct answer is (d); ///athens had a small population;

the perimeter of a triangle is 69 cm. side a is 5 cm shorter than side b. side c is twice as long as side a. find the length of each side. i need to know how to do it in 2 equations.  

equations:

a = b-5

c = 2a

a + b + c = 69

the answer should be founding brothers. i hope i you!