Question

solve the system by substitution

-x - y - z = -8
-4x + 4y + 5z = 7
2x + 2z = 4

Answer 1

so manipulate the first equation to make it x = something

Answer 2

i have no idea how to get rid of the -y and -z

Answer 3

Cry

Answer 4

but its using substitution not elimination

Answer 5

I am going to take a gander and say that you are in Algebra 1

Answer 6

no algebra 2, i think its suppose to be a review but i never learned this.

Answer 7

Omy I swear if i have to learn this again o_o

Answer 8

But yes this is review from Algebra 1 I hated these things

Answer 9

im doing online school this year so they probably have it different i dont kknow hahah

Answer 10

Haha I am too but I have been doing it for like 2 years now

Answer 11

if you rearrange the first formula then you can use it to substitute into the next ones

Answer 12

yeah im failing haha. i hate it.

Answer 13

Omy o_o But I must say I am sorry I do not know substitution ._.

Answer 14

Sad face

Answer 15

its alright. neither do i ;)

Answer 16

Ding Ding Ding I remember

Answer 17

So you are given 3 equations

Answer 18

yes

Answer 19

basically you have to solve one of them and we will go from there

Answer 20

the question is which ._. because your school was so nice and give us 3 variables... yay

Answer 21

i know i cant find any examples that have 3 :/

Answer 22

i did :p so one moment

Answer 23

Found out how :3

Answer 24

how??

Answer 25

sigh but none of yours cancels out ┻━┻ ︵ヽ(`Д´)ﾉ︵ ┻━┻

Answer 26

idea take the 1st to equations and multiply them by eachother

Answer 27

ill just be like this question is stupid lol

Answer 28

see what grade i get hahaha

Answer 29

so -5x+3y+4z=-1

Answer 30

o-O how

Answer 31

because you added the 1st line and the second line

-x - y - z = -8
-4x + 4y + 5z = 7

Answer 32

how is substitution different than elimination

Answer 33

because basically you are going to have to substitute it into a equation for x y or z depending on the situation

Answer 34

But sadly my mind is tangled I have never had to deal with more than 2 variables

Answer 35

here is a video that may help but I don't know http://www.youtube.com/watch?v=a3S2NQJYI5o

Answer 36

thank you!!

Answer 37

I can help if you still have problems

Answer 38

Yes please do because this is tangling my brain ._. I can only do 2 variables not 3

Answer 39

ok so start with re arranging the fist formula so you have x =
what do you get

Answer 40

are you having problems?