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Question 345986: Answer the question and solve the problems below. Make sure you show all your work so you can get partial credit even if you get the final answer wrong.
1. What is a system of equations?
2. Solve for X and Y in the following problems using either substitution or elimination methods. Make sure you show all your work so you can get partial credit even if your final answer is wrong.
a. X + Y = 10 , 3X + Y = 12
b. 2X + 5Y = 19 , 3X + 3Y = 15
c. 4X + Y = 22 , 2X + 3Y = 16
d. 12X + Y = 174 , 8X - 2Y = 36
3. Suppose Bob owns 2,000 shares of Company X and 10,000 shares of Company Y. The total value of Bob's holdings of these two companies is $372,000.
Suppose Frank owns 8,000 shares of Company X and 6,000 shares of Company Y. The total value of Franks holdings of these two companies is $400,000.
a. Write equations for Bob and Frank's holdings. Use the variables X and Y to represent the values of shares of Company X and Company Y.
b. Solve for the value of a share of Company X and Company Y. Show your work so you can get partial credit even if your final answer is wrong.
4. Solve for X, Y, and Z in the following systems of three equations using either substition or elimination methods:
a. X + 2Y + Z = 22
X + Y = 15
3X + Y + Z = 37
b. 10X + Y + Z = 603
8X + 2Y + Z = 603
20X - 10Y - 2Z = -6
c. 22X + 5Y + 7Z = 12
10X + 3Y + 2Z = 5
9X + 2Y + 12Z = 14
Answer by JBarnum(2146)   (Show Source):
You can put this solution on YOUR website! sry i dont have time to do all those questions but as for the #4
a) you should be able to do in your head using elimination method.
X + 2Y + Z = 22
X + Y = 15
3X + Y + Z = 37
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X + 2Y + Z = 22
-(X + Y = 15)
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Y + Z = 7
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3X + Y + Z = 37
-(Y + Z = 7)
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3X=30
X + Y = 15
Y + Z = 7
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b)start with the first two
10X + Y + Z = 603
8X + 2Y + Z = 603
20X - 10Y - 2Z = -6
10X + Y + Z = 603
-(8X + 2Y + Z = 603)
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2X - Y = 0
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2X - Y = 0 (multiply this whole thing by 10)
20X - 10Y = 0
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20X - 10Y - 2Z = -6
-(20X - 10Y = 0)
-2Z = -6
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