Question

Given matrix
[1 2 3| -1]
[2 1 -1| 2]
[-1 0 5| 7]
What will be the new second row after the row operation: R2-2R1+R3?

a. [0, -3, -7 |4]

b. [-1, -3, -2 | 11]

c. [1, 1, 4 | 9]

d. [0, 0, 1 | 2]

Answer 1

R2-2R1 = [2 1 -1 | 2] - 2[1 2 3 | -1]
= [2 1 -1 | 2] - [2 4 6 | -2]
= [0 -3 -7 | 4]
Now do +R3