Line c has a positive slope since it goes from -5 to -3. and kind d’s slope is 2/5 which is also positive so the answer is a)
[ Answer ]

[ Explanation ]
- System Of Equations

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- Isolate x for x + x + 10 = 10: x = 0
For y = 10
Substitute x = 0
Y = 0 + 10
0 + 10 = 10
y = 10
X = 0
Y = 10
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Answer:
$38.31
Step-by-step explanation:
Given:
Pure silver that cost $33.48 per ounce used to form $24.35 alloy/ounce.
Question asked:
How many ounces of pure silver were used to make an alloy of silver costing $27.87 per ounce?
Solution:
At cost $24.35/ounce, pure silver is mixed = $33.48
At cost $1/ounce, pure silver is mixed = 
At cost $27.87/ounce, pure silver is mixed = 

Thus, $38.31 ounces of pure silver were used to make an alloy of silver costing $27.87 per ounce.
Answer:
(2, 7, 1)
Step-by-step explanation:
We have three equations, and using Gauss-Jordan Elimination, we can solve for x, y, and z
3x + y - 2z = 11
4x - 2y + z = -5
x + 5y - 4z = 33
We can start by taking out the z from all rows except one. To do this, we can work with the second row. I chose the second row because -5 is small and easy to add up with other numbers, and z has no coefficient in this row.
We can add 2 times the second row to the first row and 4 times the second row to the third row to get
11x - 3y = 1
4x - 2y + z = -5
17x -3y = 13
We then have the first and third rows having two variables. Since the y coefficients are the same, we can eliminate the y by adding the negative of the first row to the third row. Our result is then
11x - 3y = 1
4x - 2y + z = -5
6x = 12
From the third row, we can gather that x= 2. We can then plug that into the first row to get
22 -3y = 1
subtract 22 from both sides
-3y = -21
divide both sides by -3
y = 7
We can then plug our x and y values into the second row to get
4(2) - 2(7) + z = -5
8 - 14 + z = -5
-6 + z = -5
add 6 to both sides
z = 1
Our answer is thus (2, 7, 1)