Answer:

Step-by-step explanation:
As the given Augmented matrix is
![\left[\begin{array}{ccccc}9&-2&0&-4&:8\\0&7&-1&-1&:9\\8&12&-6&5&:-2\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccc%7D9%26-2%260%26-4%26%3A8%5C%5C0%267%26-1%26-1%26%3A9%5C%5C8%2612%26-6%265%26%3A-2%5Cend%7Barray%7D%5Cright%5D)
Step 1 :
↔
![\left[\begin{array}{ccccc}1&-14&6&-9&:10\\0&7&-1&-1&:9\\8&12&-6&5&:-2\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccc%7D1%26-14%266%26-9%26%3A10%5C%5C0%267%26-1%26-1%26%3A9%5C%5C8%2612%26-6%265%26%3A-2%5Cend%7Barray%7D%5Cright%5D)
Step 2 :
↔
![\left[\begin{array}{ccccc}1&-14&6&-9&:10\\0&7&-1&-1&:9\\0&124&-54&77&:-82\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccc%7D1%26-14%266%26-9%26%3A10%5C%5C0%267%26-1%26-1%26%3A9%5C%5C0%26124%26-54%2677%26%3A-82%5Cend%7Barray%7D%5Cright%5D)
Step 3 :
↔
![\left[\begin{array}{ccccc}1&-14&6&-9&:10\\0&1&-\frac{1}{7} &-\frac{1}{7} &:\frac{9}{7} \\0&124&-54&77&:-82\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccc%7D1%26-14%266%26-9%26%3A10%5C%5C0%261%26-%5Cfrac%7B1%7D%7B7%7D%20%26-%5Cfrac%7B1%7D%7B7%7D%20%26%3A%5Cfrac%7B9%7D%7B7%7D%20%5C%5C0%26124%26-54%2677%26%3A-82%5Cend%7Barray%7D%5Cright%5D)
Step 4 :
↔
,
↔
![\left[\begin{array}{ccccc}1&0&4&-11&:-8\\0&1&-\frac{1}{7} &-\frac{1}{7} &:\frac{9}{7} \\0&0&- \frac{254}{7} &\frac{663}{7} &:-\frac{1690}{7} \end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccc%7D1%260%264%26-11%26%3A-8%5C%5C0%261%26-%5Cfrac%7B1%7D%7B7%7D%20%26-%5Cfrac%7B1%7D%7B7%7D%20%26%3A%5Cfrac%7B9%7D%7B7%7D%20%5C%5C0%260%26-%20%5Cfrac%7B254%7D%7B7%7D%20%26%5Cfrac%7B663%7D%7B7%7D%20%26%3A-%5Cfrac%7B1690%7D%7B7%7D%20%5Cend%7Barray%7D%5Cright%5D)
Step 5 :
↔
![\left[\begin{array}{ccccc}1&0&4&-11&:-8\\0&1&-\frac{1}{7} &-\frac{1}{7} &:\frac{9}{7} \\0&0&1&-\frac{663}{254} &:-\frac{1690}{254} \end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccc%7D1%260%264%26-11%26%3A-8%5C%5C0%261%26-%5Cfrac%7B1%7D%7B7%7D%20%26-%5Cfrac%7B1%7D%7B7%7D%20%26%3A%5Cfrac%7B9%7D%7B7%7D%20%5C%5C0%260%261%26-%5Cfrac%7B663%7D%7B254%7D%20%26%3A-%5Cfrac%7B1690%7D%7B254%7D%20%5Cend%7Barray%7D%5Cright%5D)
Step 6 :
↔
,
↔
![\left[\begin{array}{ccccc}1&0&0&-\frac{71}{127} &:\frac{176}{127} \\0&1&0&-\frac{131}{254} &:\frac{284}{127} \\0&0&1&-\frac{663}{254} &:\frac{845}{127} \end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccccc%7D1%260%260%26-%5Cfrac%7B71%7D%7B127%7D%20%26%3A%5Cfrac%7B176%7D%7B127%7D%20%5C%5C0%261%260%26-%5Cfrac%7B131%7D%7B254%7D%20%26%3A%5Cfrac%7B284%7D%7B127%7D%20%5C%5C0%260%261%26-%5Cfrac%7B663%7D%7B254%7D%20%26%3A%5Cfrac%7B845%7D%7B127%7D%20%5Cend%7Barray%7D%5Cright%5D)
∴ we get

Answer:
UMAMI I think may be the answer to your question
To find the answer for A you add up the interest rate for 2 years which is 16% then find 16% of $9,000 which is $1,440 and that's his interest rate he will have to pay for 2 years. If you want to know how much he has to pay in total for 2 years you simply just add the interest rate $1,440to $9,000 and you get $10,440.
To find the answer for B you add up the interest rate for 6 years which is 48% then find 48% of $9,000 which is $4,320 and that's his interest rate he will have to pay for 6 years. If you want to know how much he has to pay in the total 6 years you simply just add the interest rate $4,320 to $9,000 and you get $13,320.
I hope that helped you.
So you are gonna have to subtract the area with the numbers given and round that answer to the the nearest 1/10! I hope this answers your question... or helps you solve it!!!!!
In order to solve how many problems each person has solved, you have to multiply the fraction by the number of problems on their assignment. To do this, you multiply the numberator by the number of problems and then divide that by the denominator for both Dustin and Kelsey.
For Dustin, 3/8 * 24 = 72 / 8 = 9 problems completed
For Kelsey, 4/15 * 30 = 120/15 = 8 problems completed
Dustin has completed more problems