How do historians build and support their historical arguments?

The methods that historians utilize to write history differs based on their perspective and interest. But, many begin with some similar research methods. Basically, they're factors like philosophy and focus that make writing history unique to the historians.

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c) legal battles last five weeks after the election due to the narrow victory in several states.

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