Question

Steps to solving:
8x - 2y + z= -6
-x + 3y - 2z= -15
3x - y + 4z= 13

Answer 1

Multiply the second equation with 8 then add the first two equation x will get cancelled
let me know what you get after addition.

Answer 2

ok hold on

Answer 3

i got 22y-15z=-126

Answer 4

yes this is correct.

Answer 5

ok now multiply again the second equation with 3 and add this with the equation 3.
multiply the second equation this one with 3
-x + 3y - 2z= -15
then add it with
3x - y + 4z= 13
let me know what you get after addition

Answer 6

i got 8y-2z=-32

Answer 7

correct

Answer 8

now you have two equations with two unknowns, y and z
22y-15z=-126
8y-2z=-32

can you find y and z from these equations ??

Answer 9

using the elimination process i multiplied the new #1 equation by by 8 and the 2nd new equation by 2 and got :
-176y+120z=1008
(+)176y-44z=-64
______________________
and got z=12.4

Answer 10

is that correct?

Answer 11

if so, then just plug-in z to get x and y :)

Answer 12

i did and got x= -5.9 & y= -14.4 but when i plug it in into one of the original equation the values don't work.

Answer 13

Actually wendy, you should try solving again. I got 4 for z.

Answer 14

wait yes it did work i check it .

Answer 15

So tell me what you have for x and y if z=4.

Answer 16

oh but how come then it works because i also used a linear equation solver in the internet and it also had z=4 so that's why im confused and i got -5.9 for x and -14.4 for y

Answer 17

It's because when you were eliminating, you multiplied 2 instead of 22. =P
check your work.

Answer 18

using the elimination process i multiplied the new #1 equation by by 8 and the 2nd new equation by 2 and got :
-176y+120z=1008
(+)176y-44z=-64
______________________
and got z=12.4


See that's what you did. You were supposed to get 704 as a constant.
Not -64

Answer 19

sorry guys i was doing my little work:P
so where we are ?

Answer 20

@wendy67 is trying to figure out why she isn't getting z=4....

Answer 21

22y-15z=-126
8y-2z=-32
did you solve it ?

Answer 22

hmm.......

Answer 23

ok let me do this.

Answer 24

she eliminated wrong

Answer 25

in the system you gave her @sami-21

Answer 26

when i did this
22y-15z=-126
8y-2z=-32
i multiplied the eq#1 by 8 and eq#2 by 22
and when i mulitplied the sencond equation by 22 the constant is 704 but i got -704

Answer 27

-176y+120z=1008
(+)176y-44z=-704nd
______________________
so z=4

Answer 28

solve equation two 8y-2z=-32 for z
-2z=-32-8y
z=16+4y
and put in 1 22y-15z=-126
tell me what you get for y.

Answer 29

@wendy67

Answer 30

so instead of solving for z solve for y?

Answer 31

ok let me do this
solve equation two 8y-2z=-32 for z
-2z=-32-8y
z=16+4y put this value of z in
22y-15z=-126
22y-15(16+4y)=-126
22y-240-60y=-126
-44y=-126+240
-38y=114
y=-114/38
y=-3
now put this in any of the above two equations i am putting in 8y-2z=-32
8(-3)-2z=-32
-24-2z=-32
-2z=-32+24
-2z=-8
z=4

now use these value of y and z in any of the , original 3 equations given in the question to get x.

Answer 32

i hope it is clear now :)

Answer 33

ok i figuered out what i did wrong so i took z=4 and pluged it into the 2nd original equation
-x=3y-2(4)=-15
-and got x=7

Answer 34

is that correct

Answer 35

nopes ! look at what i got for y and z then using these value find the value of x

Answer 36

x=-2?

Answer 37

yes !

Answer 38

ok to get myself clearer when i solve for z which 4 then i plug it in into and original equation and solve for y and whatever i get for y plug it back in into and original equatin and solve for x?

Answer 39

*and=an* srry

Answer 40

nevermind i re-did it following through everything we all discussed and got it cleared thanks @sami-21 and @xThatOneKidx :)

Answer 41

you are welcome:)