Answer:

Explanation:
A system of equations is a set of two or more equations with the same variables. It allows us to model and solve problems that involve multiple equations and unknowns.
An investment firm recommends that a client invest in bonds rated AAA, A, and B. The definition of the variables are:
- Let x be the number of AAA bonds.
- Let y be the number of A bonds.
- Let z be the number of B bonds.
The average yield on each of the three bonds is:
- AAA bonds = 4%
- A bonds = 6%
- B bonds = 12%
We have been told that the total investment is $35,000. Therefore, the equation that represents this is the sum of the three investments equal to 35,000:

To find the annual return on each investment, multiply the number of bonds by the average yield (in decimal form). Given the investor wants a total annual return of $1940 on the three investments, the equation that represents this is the sum of the product of the investment amount for each bond type and its corresponding yield, equal to $1940.

Multiply all terms by 100:

Finally, given the client wants to invest twice as much in A bonds as in B bonds, the equation is:

Subtract y from both sides of the equation:

Therefore, the system of equations the models the given scenario is:
