With mathematics hw show all the work for each problem given geniuses

7. A great way to do this is to use a recursive routine on a calculator. 
Begin with {5000,0} to represent the starting amount of money and years passed. Hit enter. Then, put in: {Ans(1)x1.06,Ans(2)+1}. 
The first part adds the compounded interest and the second adds a year.
Hit enter until the second value equals 8. You get {7969.24037265,8}. 
Round that to the nearest cent to get $7,969.24 as the investment's value after 8 years. 

9. Let's use the recursive routine again. 
Begin with {1,1} to represent the starting 1 mile on week 1. Hit enter. 
For the second part, use {Ans(1)x1.2, Ans(2)+1}. The first part increases the number of miles and the second goes to the next week. Hit enter until the second value is 10. The result is {6.1917364224,10}. The question says to round to the nearest mile, which is 6 miles. 

4. This recursive routine will be different, since it is decreasing. Instead of multiplying it by something more than one, multiply it by 0.5. Start with {100,0} for the money and weeks. Hit enter. For the second part, use 
{Ans(1)x0.5, Ans(2)+1}. Hit enter until the second value is 5. The result is 
{3.125, 5}. Round to the nearest cent to get $3.13 left after 5 weeks. 

Hope this helps!