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View Full Version : Can someone please put this [math] problem into English?


BarTopDancer
03-05-2005, 05:26 PM
Alright,

Most of you know I hate math. I've been plodding along through this class now, getting parts of it, bsing through others. But this I am just not getting. The book, the program and the tutors all explain it the same way and it's not clicking.

It's solving ordered triples (that's what the book calls it).

6x - y + z = -24 ~~~ (eq 1)
3x + 2y - 3z = -13 ~~~ (eq 2)
x - 3y + 2z = -5 ~~~~ (eq 3)

This is what I have been doing:

I solve Eq. 1 and 2, then 1 & 3 then 4 & 5 using the elimation method. No matter what I do, even if the answers I come up with are right the program says they are wrong.

Does anyone have any tips or can they explain how to do this a differnet way?

Ghoulish Delight
03-05-2005, 05:55 PM
[if the following is what you mean by "elimiation method" I appologize for repeating this]
The easiest way to do these is to multiply both sides of one of the equations so you can add it to or subtract it from one of the others. For instance:

Multipy eq2 by 2 to get 6x+4y-6z=-26

Now you can doe eq2 - eq1 which gives you 5y-7z=-2

Now, multiply eq3 by 6 and do eq1 - eq3. That gives you:

17y-11z=6



Now you have 2 equations and 2 variables. Solve those for y and z. Use those results to get x.

BarTopDancer
03-05-2005, 06:04 PM
That is what I am talking about. Everything I am reading says you have to solve the 3 equations then the two new ones created by solving the other 3. Do you have to do it that way? Spending 30 minutes on a problem to end up with the wrong answer is pretty frustrating.

Cadaverous Pallor
03-05-2005, 06:17 PM
GD says that really is the only way to do it. We're about to go out, so can't help you any more tonight...here's the answer.
x = -4 y = 1 z = 1

Stan4dSteph
03-07-2005, 07:55 AM
You can check your answers by plugging the solutions back into the equations. If they don't check, go back and double check your solution. Chances are you added or subtracted something incorrectly along the way.

Tramspotter
03-08-2005, 09:42 PM
No, no, no, the answer is 42

Now where did I put my towel?