Question

The given matrix is the augmented matrix for a linear system. Use technology to perform the row operations needed to transform the augmented matrix to reduced echelon form, and then find all solutions to the corresponding system. (If there are an infinite number of solutions use s1 as your parameter. If there is no solution, enter NO SOLUTION.)

[9 -2 0 -4 8]
[0 7 -1 -1 9]
[8 12 -6 5 -2]

(x1, x2, x3, x4)=_______

Answer 1

`x_(1) = (176)/(127) + (71)/(127)x_(4)\\\\ x_(2) = (284)/(127) + (131)/(254)x_(4)\\\\x_(3) = (845)/(127) + (663)/(254)x_(4)\\`

Explanation:

As the given Augmented matrix is

`\left[\begin{array}{ccccc}9&-2&0&-4&:8\\0&7&-1&-1&:9\\8&12&-6&5&:-2\end{array}\right]`

Step 1 :

`r_(1)`↔
`r_(1) - r_(2)`

`\left[\begin{array}{ccccc}1&-14&6&-9&:10\\0&7&-1&-1&:9\\8&12&-6&5&:-2\end{array}\right]`

Step 2 :

`r_(3)`↔
`r_(3) - 8r_(1)`

`\left[\begin{array}{ccccc}1&-14&6&-9&:10\\0&7&-1&-1&:9\\0&124&-54&77&:-82\end{array}\right]`

Step 3 :

`r_(2)`↔
`(r_(2))/(7)`

`\left[\begin{array}{ccccc}1&-14&6&-9&:10\\0&1&-(1)/(7) &-(1)/(7) &:(9)/(7) \\0&124&-54&77&:-82\end{array}\right]`

Step 4 :

`r_(1)`↔
`r_(1) + 14r_(2)` ,
`r_(3)`↔
`r_(3) - 124r_(2)`

`\left[\begin{array}{ccccc}1&0&4&-11&:-8\\0&1&-(1)/(7) &-(1)/(7) &:(9)/(7) \\0&0&- (254)/(7) &(663)/(7) &:-(1690)/(7) \end{array}\right]`

Step 5 :

`r_(3)`↔
`(r_(3). 7)/(254)`

`\left[\begin{array}{ccccc}1&0&4&-11&:-8\\0&1&-(1)/(7) &-(1)/(7) &:(9)/(7) \\0&0&1&-(663)/(254) &:-(1690)/(254) \end{array}\right]`

Step 6 :

`r_(1)`↔
`r_(1) - 4r_(3)` ,
`r_(2)`↔
`r_(2) + (1)/(7) r_(3)`

`\left[\begin{array}{ccccc}1&0&0&-(71)/(127) &:(176)/(127) \\0&1&0&-(131)/(254) &:(284)/(127) \\0&0&1&-(663)/(254) &:(845)/(127) \end{array}\right]`

∴ we get

`x_(1) = (176)/(127) + (71)/(127)x_(4)\\\\ x_(2) = (284)/(127) + (131)/(254)x_(4)\\\\x_(3) = (845)/(127) + (663)/(254)x_(4)\\`