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[SOLVED] LA 1.1.6 augmented Matrix

karush

Well-known member
Jan 31, 2012
2,620
Wahiawa, Hawaii
complete
$$\left[
\begin{array}{rrrr|r}
1& -6& 4& 0&-1\\
0& 2& -7& 0&4\\
0& 0& 1& 2&-3\\
0& 0& 4& 1&2\
\end{array}\right]$$
ok assume next step is $r_2/2$ and $r_4/4$ introducing fractions
 
Last edited:

Cbarker1

Active member
Jan 8, 2013
227
MN
Yes for $r_2/2$. But no for $r_4/4$. You need to multiply by the value from above and below by the given row value. So for instance, you multiple by -4 on fourth row and then add them to the 5th row.
 

karush

Well-known member
Jan 31, 2012
2,620
Wahiawa, Hawaii
how about $r_2/2$.and $r_4-r_3(- 4)$
 

Cbarker1

Active member
Jan 8, 2013
227
MN
complete
$$\left[
\begin{array}{rrrr|r}
1& -6& 4& 0&-1\\
0& 2& -7& 0&4\\
0& 0& 1& 2&-3\\
0& 0& 4& 1&2\
\end{array}\right]$$
ok assume next step is $r_2/2$ and $r_4/4$ introducing fractions
What is the complete question for this exercise?

It should be -7R4+R3=> R3. Then it follow that the R4= {0,0,1,2} and R3= {0,0,0,-14}, where {} means the row entries.
 

karush

Well-known member
Jan 31, 2012
2,620
Wahiawa, Hawaii
Consider each matrix in Exercises 5 and 6 as the augmented matrix of a linear system. State in words the next two elementary row operations that should be performed in the process of solving the system.

so it looks like the idea is to get the zeros triangle a complete solve would be complicalted
 
Last edited:

Cbarker1

Active member
Jan 8, 2013
227
MN
Where is the zeros triangle needs to be on the bottom of the matrix or the top of the matrix?
 

karush

Well-known member
Jan 31, 2012
2,620
Wahiawa, Hawaii
bottom already has the zeros except one

symbolab answer

$$\begin{bmatrix}1&0&0&0&28\\ 0&1&0&0&\frac{11}{2}\\ 0&0&1&0&1\\ 0&0&0&1&-2\end{bmatrix}$$
 

Cbarker1

Active member
Jan 8, 2013
227
MN
I see, Gauss-Jordan Elimination.