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

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  • ?
    Lv 7
    5 months ago

    See below for matrix operations and result:

    Attachment image
  • 5 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)

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