Question

solve the system by elimination -2x+2y+3z=0 -2x-y+z=-3 2x+3y+3z=5

Answer 1

@tigerlover

Answer 2

i need help

Answer 3

@kaylak12345 Gaussian elimination?

Answer 4

yes

Answer 5

Write the augmented matrix first.

Answer 6

-2 2 3 0
-2 -1 1 -3
2 3 3 5

Answer 7

apply R2=R2-R1 and R3=R3+R1. then the result is?

Answer 8

what is r

Answer 9

row

Answer 10

2nd row(new)=2nd row(old)-1st row(old).
3rd row(new)= 3rd row(old)+1st row(old)

Answer 11

2 -1 -2 -3 for r2?

Answer 12

try again..

Answer 13

what i am trying is to make all the elements of the first column expect the first to be zero

Answer 14

now m lost

Answer 15

could you example with row 1 and 2 andlet me try 2 and 3

Answer 16

0 -1 -2 -3 im lost

Answer 17

To check you answer go
http://www.wolframalpha.com/input/?i=solve+-2x%2B2y%2B3z%3D0,+-2x-y%2Bz%3D-3,+2x%2B3y%2B3z%3D5

Answer 18

i have to show my work

Answer 19

check the attachment

Answer 20

I will help you..

Answer 21

so what after that

Answer 22

did you understood how i got it?

Answer 23

somewhat

Answer 24

Its what I told, we want to make all the elements below the first element of column 1 to be zero

Answer 25

thats why i told you to subtract the 1st row from 2nd and add the 3rd and first row elements

Answer 26

oh now im getting it still kinda lost but understanding it btter

Answer 27

okay... the basic concept is to make an upper triangular matrix and then use back substitution

Answer 28

now we will make the element below -3 of second row 0. i.e. we want to make the 5 in the second column to be 0

Answer 29

5-3=2-2=0

Answer 30

right

Answer 31

for it. apply R3=R3+(5/3)R2

Answer 32

the 3rd row will be 0 0 8/3 0

Answer 33

was i right

Answer 34

no 5-3 is not 2-2

Answer 35

−2+2y+3z=0

2y+3z−2+2=0+2
2y+3z=2

2y+3z+−3z=2+−3z
2y=−3z+2

2y/2 =−3z+2/2
y =−3/2z + 1

Answer 36

is this y

Answer 37

−2x−y+z=−3

−2x−y+z+y=−3+y
−2x+z=y−3

−2x+z+−z=y−3+−z
−2x=y−z−3

−2x/−2 = y−z−3/−2
x =−1/2y +1/2z +3/2

Answer 38

and x

Answer 39

elisaab gave the solution in the attachment