# Help with row operations? Matrixes?

[1 1 2 5 ]

[2 3 −6 6 ]

[−4 −8 2 6 ]

First: −2R1+R2→R2

Second: 4R1+R3→R3

Third: 4R2+R3→R3

Perform each row operation in the order specified. What would be the final result?

### 2 Answers

- RaymondLv 75 months ago
R1 means row 1

-2R1 means -2 times row 1 (each element is multiplied by -2

-2R1 + R2 means that you add them together (element by element -- 1st with 1st, 2nd with 2nd, and so on)

→R2 means This result becomes your new row 2.

R1 = [ 1 1 2 5 ]

therefore, -2R1 will be

[-2 -2 -4 -10]

add this to row 2

[-2 -2 -4 -10] + [ 2 3 -6 6] = [ 0 1 -10 -4 ]

This is your new row 2

You now have a new matrix, where row 1 and row 3 are the same as before, but row 2 is now this new row.

The second operation:

multiply the original row 1 by 4

[ 4 4 8 20 ]

Add that to row 3.

The result will become the NEW row 3

The third operation asks you to use these new rows (2 and 3) in order to find a new-new row 3

The final matrix will be

the original row 1 (we never changed it)

the new row 2 (changed with the first operation)

the new-new row 3 (it was changed twice, here you should only show the last one)