How do you find a positive/negative interval?

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?

Type the correct answer in each box. use numerals instead of words. the average number of subscribers to an online magazine each year from 2010 to 2015 is given in the table below. the average number of subscribers to the online magazine in 2010 was the percent increase in the average number of subscribers in 2011 to the average number of subscribers in 2012 was %. the maximum average number of subscribers to the online magazine in the years shown was

Larry wants to buy some carpeting for his living room. the length of the room is 4 times the width and the total area of the room is 16 square meters. what is the length of the living room