System of three Equations

[jkitfc]

Hi guys, please see my system of three equations with 3 unknowns!
Would you please be able to help me with operations.. e.g.,

Times Eq 2 by 5 and subtract it from equation 1 for example

[FONT=arial, helvetica, clean, sans-serif]Thanks,

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[stapel]

Your sideways image is hard to read. I think you have this (after changing variable names):

. . . . .6x - y = 10

. . . . .-x + 12y + 2z = 4

. . . . .-3x + 2y + 8z = -2

Hi guys, please see my system of three equations with 3 unknowns! Would you please be able to help me with operations..

Times Eq 2 by 5 and subtract it from equation 1 for example

There is no one "right" way to do the operations. You just do whatever seems useful to you at the moment. Part of the point of this exercise is for you to learn how to figure out steps for yourself.

For instance, you have a -1x as the leading term for one of the rows. A "1" is helpful in getting rid of other stuff. By what would you multiply this line, in order to cancel the +6x in the first row? By what would you multiply this line in order to cancel the -3x from the third row?

Do the multiplications, then do the additions (or subtractions, if you prefer), and write out the new system. Then proceed from there.

If you get stuck, please reply showing your steps so far. Thank you!

 

[Steven G]

Hi guys, please see my system of three equations with 3 unknowns!
Would you please be able to help me with operations.. e.g.,

Times Eq 2 by 5 and subtract it from equation 1 for example

Thanks,

Denis is correct (5 hours in the corner for me) when he says to eliminate z first. The reason is because your 1st goal is to get two equations with the same two unknown ( so you can solve for those two variables). Since equation 1 just has variables x and y you are already half way there in getting two eqs with just x and y.

 

[Steven G]

I'm already there (Sir Khan's fault)...
bring pencil/paper, so we can play X and O's; I start :cool:

Will you be X or O? I know which one always wins so don't try to cheat me. To decide who gets to pick their letter we will flip a coin--Heads I win and tails you lose.

 

[Harry_the_cat]

Will you be X or O? I know which one always wins so don't try to cheat me. To decide who gets to pick their letter we will flip a coin--Heads I win and tails you lose.

To make it more interesting in the corner you two, try playing noughts and crosses with a slight rule change. This time you have to try to lose (ie force your partner to win).
Losers are winners. Great game - messes with your mind just a little!