A. 5×20
x=100
check
 100/5=20
 20=20 
b. 15=30/2
 ×2. ×2
30=30.
check. 
 30/2=15
 15=15 
Hope this helps..
        
             
        
        
        
What did Themistokles believe about the Persian defeat at Marathon?It was only the prelude to a greater struggle.When did the Persian Empire dominate the international political scene?For the 300 years from mid 6th century until it's conquest by Alexander of Macedon.Where could the influence of the Persian Empire be found?Both in the foreign policies of Greek states and in their own internal disputesExplain the formation of the Delian league.A direct result of the Greek conflict with Persia and the war proposed by Philip and carried out by Alexander.Explain the cultural impact of Darius and Xerxes invasion of Greece?The subject/background of some of the most celebrated works of Greek literature (such as histories of Herodotes and some plays of Aischylos)How is Persia usually characterized and how was this view developed?<span>A typical "Oriental" despotic monarchy. Developed partly as an 18th + 19th Century Western European response to what constituted "Oriental".</span>
        
             
        
        
        
Vikings transports us to the brutal and mysterious world of Ragnar Lothbrok, a Viking warrior and farmer who yearns to explore - and raid - the distant shores across the ocean.
        
             
        
        
        
Answer:
I Believe the answer is: Personal records Personal record revers to a form of primary source which information is derived from the observation or the experiments that being done by the source writers themselves. In most cases, personal records are created by experts on the relevant fields. 
Explanation: