2x + y = 9
2x - 5y = 15
Subtract the 2nd equation from the 1st.
6y = -6
y = -1
Substitute for y in 1st equation.
2x - 1 = 9
2x = 10
x = 5
Check in 2nd equation.
2(5) -5(-1) = 15
10 + 5 = 15
15 = 15
Perhaps your 2nd problem expression should be written as
-13/(1-2x)
And disallowed is any value of x that makes (1 - 2x) equal to zero (division by zero is undefined).
2006-07-19 05:35:32
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answer #1
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answered by Anonymous
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There are many methods, for example:
2x - 5y = 15 , 2x = 15 + 5y. Now replace to the first equation:
y = 9 - (15 + 5y), y = 9 - 15 - 5y, 6y = -6, y = -1.
Replacing to the first, we have:
-1 = 9 - 2x, 2x = 9 + 1, 2x = 10, x = 5.
So the solution is: x = 5, y = -1.
2006-07-19 12:49:12
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answer #2
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answered by Dimos F 4
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First thing you need to do is to rewrite the set of equations like this:
2x + y = 9
2x - 5y = 15
Then solve the equation.
-(-6y) = -6
6y = -6
y = -1
Then solve for the x
(you can do the rest)
-13/1 - 2x
I am assuming you mean -13/(1-2x)
Then you can not have a value of x where 1-2x would be zero
which would be x=0.5
2006-07-19 12:27:01
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answer #3
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answered by tkquestion 7
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y = 9 - 2x
2x - 5y = 15
2x - 5(9 - 2x) = 15
2x - 45 + 10x = 15
12x - 45 = 15
3(4x - 15) = 15
4x - 15 = 5
4x = 20
x = 5
y = 9 - 2x
y = 9 - 2(5)
y = 9 - 10
y = -1
x = 5
y = -1
2006-07-19 23:12:17
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answer #4
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answered by Sherman81 6
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y = 9-2x
2x-5y = 15
2x-5(9-2x) = 15
2x-45-10x = 15
-45-8x = 15
-8x = 60
x = -7.5
y = 9-2x
y = 9+15
y = 24
Therefore, x = 9, and y = 24.
EDIT: uhh, sorry, can you make your second problem a little clearer?
All I can tell you is that -13/1-2x could mean (-13/1) - 2x, or -13/(1-2x).
2006-07-19 12:23:18
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answer #5
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answered by Anonymous
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y = 9 - 2x (eqn 1)
2x - 5y = 15 (eqn 2)
substracting (eqn 2) from (eqn 1), we have
6y = -6
hence, y= -1 Substituting this value in (eqn 1), we have
2x = 10
hence, x=5
therefore solution set is (5,-1)
2006-07-19 12:29:55
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answer #6
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answered by kmr.rohit 1
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the answer is 7. no 9. no 3. no 2. no 5. no 10........what's the question?
2006-07-19 12:24:28
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answer #7
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answered by Anonymous
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y= -1
x = 5
2006-07-19 12:26:24
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answer #8
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answered by nobody722 3
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