Question

Solve the system:
3x-y=-1
2x-y+z=-6
x+4y-z=9

Answer 1

\[x+4y-z=9\]\[3x-y=-12\]\[x-y+z=-6\] Is this system correct?

Answer 2

no. 3x-y=-1
2x-y+z=-6
x+4y-z=9

Answer 3

Step1: Take any equation. Let's say 2.

Solve it for any variable. Let's say z.
It will look like: z = -6 + y - 2x

Now take eq 3.
Solve it for z.
z = x + 4y + 9

Answer 4

Final thing.
eq 2 = eq 3
-6 + y - 2x = x + 4y + 9

Simplify.

Answer 5

with this you add all the like factors right?

Answer 6

You will get something like equation 1.

Then solving that equation and equation 1 simultaneously will give you value of x and y

Answer 7

im so confused

Answer 8

and i have 2 more problems like this

Answer 9

-6 + y - 2x = x + 4y + 9
Simplify.

-15 = 6y + 3y

Do you get till here?

Answer 10

how did you get 6y when it is 4y and a y wouldnt it be 5y and why is there two ys shouldnt there be an x so no i dont get it

Answer 11

Sorry. Did a typo.
-6 + y - 2x = x + 4y + 9
Simplify.

-15 = 3x + 3y

Do you get till here?

Answer 12

yes

Answer 13

Now take this equation AND equation 1
-15 = 3x + 3y
AND
3x-y=-1

Solve both of these.

Answer 14

how? i have questions like that i need help with to

Answer 15

You can solve this by elimination or substitution.

Answer 16

i know that i get confused doing it.. I did a couple but then some i got confused on can give me the steps please on how to do it so that i can do it on the others i need help with and use that example

Answer 17

to look back to if that makes since

Answer 18

Just out of curiosity, from how many decades you haven't been doing your homework? XD

Answer 19

Is your computer still locked?

Answer 20

yes.. and what was your last question?

Answer 21

You have soo much homework! D:

I can send you links for examples but your computer won't allow.. How can you use Openstudy?

Answer 22

my mom unlocked it for me but she is busy and i now i have tons of homework it is because i just had surgery and need to catch up

Answer 23

you can try and use the links and i can see if it works

Answer 24

Ohh.
http://www.khanacademy.org/math/algebra/systems-of-eq-and-ineq/v/the-substitution-method

Answer 25

nope doesnt work

Answer 26

http://openstudy.com/study#/updates/4ff5046be4b01c7be8c83029

Answer 27

that one worked

Answer 28

http://www.youtube.com/watch?v=uzyd_mIJaoc

Answer 29

ok let me see if i did this right..
15=3x+3y
1=3x-y
correct

Answer 30

then i multiplied -15=3x+3y by -1 so that the 3x would become a negative
so that made it 15=-3x-3y
so the x's cancelled out which made it
15=-3y
1=-y
then that was
16=-4y then i added 4 on each side to get y by it self
and that became 20 y
is that right so far

Answer 31

so y=20 so i plugged that in
15=3x+3(20)
1=3x-20
15=3(x)=60
1=3x-20
16=6x+40 then i subtracted 16 on each side
so it became 6x+24
and i dont know wheather to subtract the 6 and get x=18
or divide and get x=4