Solve the system by finding the reduced row-echelon form of the augmented matrix.

x-4y-2z=2

2x-11y-10z=13

-x+6y+6z=-8

reduced row-echelon form:


1 -4 -2 2

0 1 -10 -3

0 0 0 0

(It's wrong, and I don't know why ? )



If there is one solution, give its coordinates in the answer spaces below.

If there are infinitely many solutions, enter z in the answer blank for , enter a formula for in terms of in the answer blank for and enter a formula for in terms of in the answer blank for .


If there are no solutions, leave the answer blanks for , and empty.


How can I find my X, Y ,Z ? Is it going to be Zero ?!

Respuesta :

Answer:

The reduced row-echelon form is

[tex]\left[ \begin{array}{cccc} 1 & 0 & 6 & -10 \\\\ 0 & 1 & 2 & -3 \\\\ 0 & 0 & 0 & 0 \end{array} \right][/tex]

The solutions to the system of equations are:

[tex]y=-2z-3,\:x=-6z-10[/tex]

Step-by-step explanation:

To solve this system of linear equations,

[tex]x-4y-2z=2\\2x-11y-10z=13\\-x+6y+6z=-8[/tex]

you must:

Step 1: Transform the augmented matrix to the reduced row echelon form.

In an augmented matrix, each row represents one equation in the system and each column represents a variable or the constant terms.

This is the augmented matrix that represents the system.

[tex]\left[ \begin{array}{cccc} 1 & -4 & -2 & 2 \\\\ 2 & -11 & -10 & 13 \\\\ -1 & 6 & 6 & -8 \end{array} \right][/tex]

It can be transformed by a sequence of elementary row operations to the matrix.

There are three kinds of elementary matrix operations.

  1. Interchange two rows (or columns).
  2. Multiply each element in a row (or column) by a non-zero number.
  3. Multiply a row (or column) by a non-zero number and add the result to another row (or column).

Using elementary matrix operations, we get that

Row Operation 1: add -2 times the 1st row to the 2nd row

Row Operation 2: add 1 times the 1st row to the 3rd row

Row Operation 3: multiply the 2nd row by -1/3

Row Operation 4: add -2 times the 2nd row to the 3rd row

Row Operation 5: add 4 times the 2nd row to the 1st row

[tex]\left[ \begin{array}{cccc} 1 & 0 & 6 & -10 \\\\ 0 & 1 & 2 & -3 \\\\ 0 & 0 & 0 & 0 \end{array} \right][/tex]

Step 2: Interpret the reduced row echelon form

The reduced row echelon form of the augmented matrix is

[tex]\left[ \begin{array}{cccc} 1 & 0 & 6 & -10 \\\\ 0 & 1 & 2 & -3 \\\\ 0 & 0 & 0 & 0 \end{array} \right][/tex]

which corresponds to the system

[tex]x+6z=-10\\y+2z=-3\\0=0[/tex]

The system has infinitely many solutions.

[tex]y=-2z-3,\:x=-6z-10[/tex]