-2(x-4)+1=7 is solved the results is

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?

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