divide x^3 + 2x - 1 by x + 3

[NEHA]

divide
x^3 + 2x - 1 by x + 3

so

x^3 + 2x - 1
---------------
x + 3

x^3 + 3x - 2

the way i did it ..it seems to me that i did it wrong
can you correct me on this?

 

[stapel]

Where is "x^3 + 3x - 2" coming from?

Are you trying to cancel terms instead of factors...? Like "12/2 = 1, because the 2's cancel off"...?

It looks almost like you're switching signs on the terms, and then adding them, like saying "(2x + 6)/(-2) = 2x - 4, because -6 + 2 = -4"...?

Has your class not covered polynomial long division yet?

Thank you.

Eliz.

 

[NEHA]

(x^3 + 2x - 1) / (x + 3)

         x  -  1
      -------------
x + 3 ) x^3 + 2x - 1
        x^3 + 3x
       -------------
              5x - 1
             -1x - 3
       -------------
              6x - 2

Now what do I do? If I did this wrong, please explain well how to do it correctly. Thank you.
___________________________________
Edited by stapel -- Reason for edit: formatting, spelling, etc

 

[soroban]

Hello, NEHA!

I guess you don't know long division . . .

              x² - 3x + 11
      --------------------
x + 3 ) x³       + 2x -  1
        x³ + 3x²
        --------
            -3x² + 2x
            -3x² - 9x
            ---------
                  11x -  1
                  11x + 33
                  --------
                       -34

 

[Denis]

You need to "leave space" for the "x^2", ok?

         x^2  - 3x  + 11
      -------------------
x+3 / x^3 + 0x^2 + 2x - 1 
      x^3 + 3x^2
      ---------------
          - 3x^2 + 2x
          - 3x^2 - 9x
         ------------
                  11x -  1
                  11x + 33
                  --------
                      - 34