How simplify n 4-9-5n?

Powers of ten? You are four times older than your son In twenty years of time your age will be twice as your son ' s age Calculate my son ' s age? How do you solve 2 radical square root of x plus 2 end root minus 3 equals 7? What were some advantages of the alarm clock? 167 square meters is equal to how many feet? What percentage of 48750 is 1000? What is 240 divded by 8? How much is 3 feet in inches? 0.9 mile equals how many feet? How many times is the word revive in KJV bible? What is nearest hundred from 297? What grade should a 9 year old be in? Is there a remainder to 84 divided by 4? What government security pays a fixed rate of interest every six months until they mature in two to ten years? What is one half of one half of an hour? What is 4 and one third as a percentage? What goes into 13 and 6? What is Two thirds divided by three sevenths? What is 60 subtract 37? In pq4r what does the r stands for?