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Is it solvable?

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Old Jan 28, 2008 | 06:46 AM
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Default Is it solvable?

In class, while reducing matrices in an augmented form, we came up with:

x + (13/2)z = 29/2
y + -(3/2)z = -9/2

No one could answer wether or not the system had a solution, and I still can not. He said if we came up with a concise answer as to wether or not the equations were solvable, he would give us a bonus point on the first test. So, any help would be appreciated. Thanks!~
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Old Jan 28, 2008 | 07:18 AM
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Paging magician...

Sorry, no help from me.
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Old Jan 28, 2008 | 07:21 AM
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Not possible. 2 equations and 3 unknowns. You would need 3 equations to solve for 3 unknowns.
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Old Jan 28, 2008 | 08:37 AM
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3 variables with 2 equations. Your solution will be a graph, not a point.
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Old Jan 28, 2008 | 09:43 AM
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[QUOTE=S2020,Jan 28 2008, 09:37 AM]3 variables with 2 equations.
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Old Jan 28, 2008 | 09:56 AM
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It can be solveable but it has multiple soultions.

Sounds like a linear algebra class?
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Old Jan 28, 2008 | 10:12 AM
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Originally Posted by magician,Jan 28 2008, 10:43 AM
More accurately, the solution set is a line in 3-space. (A "graph" could be a line, a plane, a set of discrete points, a hyperbolic paraboloid, the interior of a cube, and so on.)

The coefficient matrix for the system is:

[1 0 13/2]
[0 1 -3/2]

and augmented matrix for this system is:

[1 0 13/2 29/2]
[0 1 -3/2 -9/2].

The dimension of the row space for the coefficient matrix is 2, as is the dimension of the row space for the augmented matrix; thus, the system is soluble. The dimension of the solution space is 3 - 2 = 1.

The solution space is the set of all points in 3-space having the form ((29 - 13t) / 2, (3t - 9) / 2, t), -∞ < t < ∞.
dang! I need to be more specific when Magicman is around!!!!!!
I got pwned.
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Old Jan 28, 2008 | 10:22 AM
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Regardless, we need to know what class you're taking. If you write down something similar to what magician posted, and such info is beyond the scope of your class, it will be evident that you asked for help on the inetrnets
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Old Jan 28, 2008 | 11:18 AM
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Business Cal, and yah I figured magician would come up with the answer, but I didn't want to rely just specifically on one person :-P.

Even while looking at his answer, I do think it's beyond what the teacher might be looking for :-P
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Old Jan 28, 2008 | 11:34 AM
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For business calc, I'd imagine so.
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