Prior to the 19th century, why were historians unsure about whether or not the Hittites actually existed?

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

answer

the statement that best describes president carter’s attempt to free the hostages in iran is c. all of the attempts failed.

explanation

the operation eagle claw conducted by the united states armed forces was a failed mission which aimed to rescue 52 americans captured as hostages in the american embassy, tehran on 24/4/1980.the mission was authorized by president jimmy carter. the failures included;   obstacles in operation that included operational conditions challenges caused by sandstorms, hydraulic problems of one the helicopters and , mechanical failure of another helicopter that was identified as a cracked rotor blade and the crashing of another helicopter during mission abortion causing death of 8 service persons.