Question

How do you put this into reduced row echelon form?

$$
\left[\begin{array}{rrr|r}
3 & -2 & -1 & -8 \\
5 & 1 & 3 & 23 \\
4 & 1 & -5 & -18
\end{array}\right]
$$

Answer 1

1) first of all divide with 3 the whole 1st row to get pivot point 1 (all other elements below it should be zero ) .
2) then subtract 4 times of row 1 from 3rd row
3) now subtract 5 times of row one from 2nd row

do this and let me know that you get .

Answer 2

@apple_pi

Answer 3

ok thanks i'll work on it

Answer 4

there are steps after this to carried out .. if you want to completely do this first do the above 3 steps and then will let you the further steps..

Answer 5

So now I have
$$
\left[\begin{array}{rrr|r}
1 & \frac{-2}{3} & \frac{-1}{3} & \frac{-8}{3} \\
0 & \frac{13}{3} & \frac{14}{3} & \frac{109}{3} \\
0 & \frac{11}{3} & \frac{-11}{3} & \frac{-46}{3}
\end{array}\right]
$$

Answer 6

@sami-21

Answer 7

1) ok now multiply the second row with 13/3 to get 1 at the first point
2) then subtract 11/3 times of 2nd row from the third row .

Answer 8

1) multiply? would that possibly be divide by 13/3?

Answer 9

@sami-21

Answer 10

i should have written to multiply with 3/13 ... yes if you divide with 13/3 same .. end result will be 1

Answer 11

ok.

Answer 12

Oh, yeah I got it from here. Thanks

Answer 13

let me give you online interactive tool for free to convert matrix to reduced ech form.
go here
http://www.math.odu.edu/~bogacki/cgi-bin/lat.cgi
select Transforming a matrix to reduced row echelon form (third one in list)
then select 3 rows and three columns
then enter the left hand part of matrix
it will teach you complete steps !