Question

Solve by elimination~please show all work!
-2x+2y+3z=0
-2x-y+z=-3
2x+3y+3z=5

I think it is no solution because when I solved for it, x=1.75, y=0, z=.5 I plugged it back into the equations and it was good for the second two, but it was wrong for the first one. Can someone please show steps to see if I did it right?

Answer 1

@SydtheKid913 @Blu-Girl @TheSmartOne please help! :) thanks!

Answer 2

So I would try subtracting the first two equations together first to have an equation with just y and z.
I could get another equation just involving y and z by adding the last two equations.
So then you could solve that 2-variable system for y and z.

Answer 3

And then go back to one of your initial equations to find x.

Answer 4

but you should see something kinda neat when you are trying to solve for y and z that will kinda give you a little more confidence about the conclusion you have already reached.

Answer 5

I'm still really confused :(

Answer 6

Thats what I did. One second and I will show you the steps I did @myininaya :)

Answer 7

This is what I did :/ sorry it's sloppy @myininaya :(

Answer 8

I think I actually made a mistake
Your first solution might be okay.
I will check it.

Answer 9

Thank you so much :)

Answer 10

I think I made the mistake. I plugged it in the calculator thingy and it should be x=1 y=1 z=0

Answer 11

\[3y+2z=3 \\ 2y+4z=2 \\ \text{ rewrite second equation as } y+2z=1 \\ \text{ so we have } \\ 3y+2z=3 \\ -(y+2z=1) \\2y=2 \\ y=1 \]
Trying to look at your work and see how you got y=1/2
...

Answer 12

Oh I see what you did

Answer 13

You just change that one number from 2 to 6

Answer 14

you had 2y+4z=2
but you wrote 2y+4z=6

Answer 15

when you were taking away from that other equation

Answer 16

that is how you got y=0

Answer 17

so that step there should have looked more like this:
6y+4y=6
-(2y+4z=2)
-------
4y=4
y=1

Answer 18

Then you would have a difference z and therefore a different x

Answer 19

Okay. thank you so much! I really appreciate it! I might need some more help, but sublimation instead for a different problem :)

Answer 20

k

Answer 21

it might be a sec because I have to rewrite all of my work :)

Answer 22

Do you see what I was talking about though? Or understand where the error occurred?

Answer 23

yes. thank you again!

Answer 24

but then z=1....

Answer 25

I found what I did....again

Answer 26

z isn't 1

Answer 27

its 0. I accidently put 2-2 as 4 :P haha I'm too tired to do math :/

Answer 28

lol

Answer 29

we all are sometimes

Answer 30

haha but now I have to rewrite it, yet again :'(

Answer 31

I'm switching to pencil now so I don't have to start over when I make a mistake :P

Answer 32

I didn't correct your check section.

Answer 33

It's okay. I got it now.....one second. I am starting the sublimation one :)

Answer 34

Okay. I have the problem now :)