Need help with homework

Sandals · 24-10-2005 6:11pm #1

Hi I need help with this problem, can you pleae help me out
For whta values of A will the following system have
no solutions?
1 solution?
infinite solutions?

x + 2y - 3z = 4
3x - y + 5z = 2
4x + y + (a squared - 14)z = A + 2

I would greatly apreciate any help.

Pherekydes · 24-10-2005 8:11pm

4 gives infinite solns, and -3 gives 1 soln.

Any other value gives no solns.

Sandals · 24-10-2005 8:12pm

how did u work that out?

Pherekydes · 24-10-2005 8:39pm

Just a wild guess. Is it right? A bit fuzzy on the old matrices at the mo'.

Sandals · 24-10-2005 8:57pm

i dont know i cant do it

breadmonkey · 24-10-2005 10:54pm

Find the determinant (do you know you're meant to do this?) and work from there using the various conditions I think. It's been a while since I've done something like this so apologies if I'm wrong.

katiegordon · 25-10-2005 5:01pm

whats the determinant?

Sandals · 25-10-2005 5:08pm

breadmonkey wrote:

Find the determinant (do you know you're meant to do this?) and work from there using the various conditions I think. It's been a while since I've done something like this so apologies if I'm wrong.

no u use gaussian methods, its ok i did it now! bitch

Tar.Aldarion · 25-10-2005 5:53pm

ah first year algebra,i miss you!

Pherekydes · 25-10-2005 9:18pm

Sandals wrote:

no u use gaussian methods, its ok i did it now! bitch

Did we get the same answers?

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