Solve a system of 3 linear equations(3 unknowns) using inverse coefficient matrix

View full question and answer details: https://www.wyzant.com/resources/answers/909360/use-the-inverse-of-the-coefficient-matrix-of-this-system-to-find-the-amount?utm_source=youtube&utm_medium=organic&utm_campaign=aae_video

Question: Use the inverse of the coefficient matrix of this system to find the amount invested in each type of bond for the given total investment and annual return.
You invest in AAA-rated bonds, A-rated bonds, and B-rated bonds. The average yields are 4.5% on AAA bonds, 5% on A bonds, and 9% on B bonds. You invest twice as much in B bonds as in A bonds. Let x, y, and z represent the amounts invested in AAA, A, and B bonds, respectively.
 

x
 + 
y
 + 
z
 = 
(total investment)
0.045x

 + 

0.05y

 + 

0.09z

 = 
(annual return)
2y

 − 
z
 = 
0

Use the inverse of the coefficient matrix of this system to find the amount invested in each type of bond for the given total investment and annual return. (Round your answers to the nearest cent.)
Total Investment      Annual Return

$12,000
    $815
amount invested in AAA-bonds     
$ 
amount invested in A-bonds 
$ 
amount invested in B-bonds 
$ 
------------------------

Answered By:

Doug C.
Math Tutor with Reputation to make difficult concepts understandable
More information: https://www.wyzant.com/Tutors/AZ/Mesa/8143904/?utm_source=youtube&utm_medium=organic&utm_campaign=aae_video

------------------------

Written Explanation:

Desmos matrix calculator:desmos.com/matrix Gaussian elimination calculator:onlinemschool.com/math/assistance/equation/gaus/
See full answer: https://www.wyzant.com/resources/answers/909360/use-the-inverse-of-the-coefficient-matrix-of-this-system-to-find-the-amount#answer-?utm_source=youtube&utm_medium=organic&utm_campaign=aae_video

------------------------

About: Wyzant Ask an Expert offers free answers to your toughest academic and professional questions from over 65,000 verified experts. It’s trusted by millions of students each month with the majority of questions receiving an answer within 1 hour of being asked. If you ever need more than just an answer, Wyzant also offers personalized 1-on-1 sessions with experts that will work with you to help you understand whatever you’re trying to learn.

Ask your own question for free: https://www.wyzant.com/resources/answers/ask?utm_source=youtube&utm_medium=organic&utm_campaign=aae_video
Find a tutor for a 1-on-1 session: https://www.wyzant.com?utm_source=youtube&utm_medium=organic&utm_campaign=aae_video
Subscribe to Wyzant on YouTube: https://www.youtube.com/subscription_center?add_user=wyzant

Видео Solve a system of 3 linear equations(3 unknowns) using inverse coefficient matrix канала Wyzant