work. Do not solve.
-5x + 9y = -12
-4x - 4y = -32
A) Substitution B) Addition
Answer: B
Write the word or phrase that best completes each statement or answers the question.
-Andy has 17 coins made up of quarters and half dollars, and their total value is $5.25. How many quarters does he have?
A) 6 quarters
B) 18 quarters
C) 13 quarters
D) 4 quarters

Question

Quizplus · Accepted Answer

First, we can set up a system of equations: 
q + h = 17 (since Andy has 17 coins total) 
0.25q + 0.5h = 5.25 (since the total value of the coins is $5.25) 
We can then use elimination to solve for q:

- Multiply the second equation by 4 to get rid of the decimals: 
q + 2h = 21 
q + 2h = 21 
- Subtract the first equation from the second: 
0 = 4 
This is not true, meaning there is no solution. However, we made a mistake along the way. Let's go back to the original equations and try again:

q + h = 17 
0.25q + 0.5h = 5.25

- Multiply the first equation by 0.25: 
0.25q + 0.25h = 4.25 
0.25q + 0.5h = 5.25 
- Subtract the first equation from the second: 
0.25h = 1 
h = 4 
- Plug h back into the first equation to find q: 
q + 4 = 17 
q = 13

Therefore, Andy has 13 quarters.

Work. Do Not Solve