Question

Solve the system by elimination.. HELP :(

Answer 1

ur still having trouble

Answer 2

its a different problem an older one

Answer 3

anyone there???????

Answer 4

yeah im trying

Answer 5

i cant help sorry

Answer 6

:P

Answer 7

okay thanks i really appreciate it. can u show ur steps so i understand more

Answer 8

who are u talking to

Answer 9

-2x -y +z = -3
2x + 3y +3z = 5
---------------
0x +2y +4z = 2 <-added together

Answer 10

huh

Answer 11

I'm not sure if the above helped...

Answer 12

okay now what @phanta_seea

Answer 13

dont i have to take the third equation and do something with that

Answer 14

I'm really just trying.....

-2x + 2y +3z = 0
2x +3y +3z = 5
--------------
0 + 5 y + 6z = 5

Answer 15

so I did two additions of original lines

now, I can add the results together as well

Answer 16

0x +2y +4z = 2
0 + 5 y + 6z = 5

want to eliminate y or z, I will eliminate y:

0 x + 10y + 20z = 10 first line * 5
-0 x - 10y - 12 z = -10 second line * -2
--------------------------------
8z = 0

Answer 17

i dont get what you did to eliminate y

Answer 18

is 8z=0 the answeR???

Answer 19

what I did was the following:

I did add row 2 and 3 --- and got a "result row 1" (R1)
then, added row 1 and 3 --- and got a "result row 2" (R2)

here are the result rows I obtained:
R1: +2y +4z = 2
R2: +5y +6z = 5

what do the result rows have that the original rows don't?
they don't have any x values to worry about.

Answer 20

@blahkatherine yep, z=0 is part of the answer, and you can use "backsubstitution" to find all the other values :)

Answer 21

so where do i plug in 0 ... which equation

Answer 22

an equation that has only one additional variable. that way you can also determine the value of the additional variable,

use one of the result rows:
R1: +2y +4z = 2
R2: +5y +6z = 5

Answer 23

ill use R1 so 2y + 4(0) = 2 so 2y + 0 =2 ... 2y = 2 ... y = 1 right?

Answer 24

true :)

Answer 25

now we know 2 variables so we can use ANY of the original rows to get x

Answer 26

So now what do i do :o

Answer 27

well you take any of the original equations and plug the z, y values

Answer 28

to find x, which is the only variable still missing

Answer 29

so my answer is y=1 and z= 0

Answer 30

oh pellet okay

Answer 31

yep, we already have y=1 and z=0

now plug those in any of the 3 original equations to get x

Answer 32

that one is right :)

Answer 33

I checked the values x=1, y=1, z=0 in all the three equations
and they're correct