SOLUTION: Perform the sequence of row operations on the matrix. (a)SwapR1 andR3. (b) Replace R2 by R2 plus -5 times R1. (C) Replace R3 by R3 plus -3 times R1. The matrix is 3 -10 -2 5

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Perform the sequence of row operations on the matrix. (a)SwapR1 andR3. (b) Replace R2 by R2 plus -5 times R1. (C) Replace R3 by R3 plus -3 times R1. The matrix is 3 -10 -2 5      Log On


   

Question 1160480: Perform the sequence of row operations on the matrix.
(a)SwapR1 andR3.
(b) Replace R2 by R2 plus -5 times R1.
(C) Replace R3 by R3 plus -3 times R1.
The matrix is
3 -10 -2
5 1 5
1 6 -1
The possible answers are
(A)
1 6 -1
0 -29 10
0 -28 1
(B)
1 5 -3
0 -17 8
0 -40 3
(C)
7 6 -7
-3 -28 1
-8 -29 10
(D)
7 6 -7
-3 -40 3
-8 -17 8
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


What is it about this that you need help with?

Simply do what it tells you to do and see what you end up with.

In case you don't understand what it is they are asking you to do, I will get you started.

The original matrix is matrix%283%2C3%2C3%2C-10%2C-2%2C5%2C1%2C5%2C1%2C6%2C-1%29

(a)Swap R1 and R3

This says switch rows 1 and 3. That will give you matrix%283%2C3%2C1%2C6%2C-1%2C5%2C1%2C5%2C3%2C-10%2C-2%29

(b) Replace R2 by R2 plus -5 times R1

This says replace row 2 with row 2 plus (-5) times row 1.
            row 2:   5   1  5
   -5 times row 1:  -5 -30  5
          -------------------
        new row 2:   0 -29 10

The matrix is now matrix%283%2C3%2C1%2C6%2C-1%2C0%2C-29%2C10%2C3%2C-10%2C-2%29

(c) Replace R3 by R3 plus -3 times R1

Similar to step (b), replace row 3 with row 3 plus (-3) times row 1.

I'll let you do that step, in the same way as shown above for step (b).

Step (c) does not change row 1 of the matrix, and only answer choice A has the correct first row, so that has to be the right answer.

You can complete the details of step (c) to verify that answer A is correct.