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C2 Polynomial

Hiya, im stuck on a C2 polynomial question. It reads:

"Divide -3x4 + 8x2 + 13x - 10 by (x - 2)"

Thanks!
Original post by JamesNeedHelp2
Hiya, im stuck on a C2 polynomial question. It reads:

"Divide -3x4 + 8x2 + 13x - 10 by (x - 2)"

Thanks!


There are various methods

Long division
Equating coefficients

What have you tried?
Original post by TenOfThem
There are various methods

Long division
Equating coefficients

What have you tried?


Long division, but i cant get past the first step. thank you
Original post by JamesNeedHelp2
Long division, but i cant get past the first step. thank you


Did you remember to put the 0x^3 in
Original post by TenOfThem
Did you remember to put the 0x^3 in


no i did not. i will work it out and put my working on here. Maybe you can help me then? thanks.
Original post by TenOfThem
Did you remember to put the 0x^3 in


"Divide -3x4 + 8x2 + 13x - 10 by (x - 2)"

Where do i put the 0x3 in? is it supposed to look like this..."-3x4 + 0x3 + 8x2 + 13x - 10 by (x - 2)"

-3x3 - 5x2 - 2x - 9

(x- 2) x (-3x3) = -3x4 + 6x3

(-3x4 + 0x3) - (-3x4 + 6x3) = (-3x4 + 0x3) + (3x4 - 6x3) = -5x3 + 8x2

(x- 2) x ( -5x2) = -5x3 + 10x2

(-5x3 + 8x2) + (5x3 - 10x2) = -2x2 + 13x

(x- 2) x (-2x) = -2x2 + 4x

(-2x2 + 4x) - (-2x2 + 13x) = -9x - 10

Answer; -3x3 - 5x2 - 2x - 9
(edited 9 years ago)
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1420787
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Put your terms in descending powers of x, so swap the first two :smile:
Original post by offhegoes
Put your terms in descending powers of x, so swap the first two :smile:


ahaaa that makes sense. thank you:smile:
Original post by offhegoes
Put your terms in descending powers of x, so swap the first two :smile:


"-3x4 + 0x3 + 8x2 + 13x - 10 by (x - 2)"

-3x3 - 5x2 - 2x - 9

(x- 2) x (-3x3) = -3x4 + 6x3

(-3x4 + 0x3) - (-3x4 + 6x3) = (-3x4 + 0x3) + (3x4 - 6x3) = -5x3 + 8x2

(x- 2) x ( -5x2) = -5x3 + 10x2

(-5x3 + 8x2) + (5x3 - 10x2) = -2x2 + 13x

(x- 2) x (-2x) = -2x2 + 4x

(-2x2 + 4x) - (-2x2 + 13x) = -9x - 10

Answer; -3x3 - 5x2 - 2x - 9
(edited 9 years ago)
Original post by JamesNeedHelp2
"Divide -3x4 + 8x2 + 13x - 10 by (x - 2)"

Where do i put the 0x3 in? is it supposed to look like this..."-3x4 + 0x3 + 8x2 + 13x - 10 by (x - 2)"

-3x3 - 5x2 - 2x - 9

(x- 2) x (-3x3) = -3x4 + 6x3

(-3x4 + 0x3) - (-3x4 + 6x3) = (-3x4 + 0x3) + (3x4 - 6x3) = -5x3 + 8x2

(x- 2) x ( -5x2) = -5x3 + 10x2

(-5x3 + 8x2) + (5x3 - 10x2) = -2x2 + 13x

(x- 2) x (-2x) = -2x2 + 4x

(-2x2 + 4x) - (-2x2 + 13x) = -9x - 10

Answer; -3x3 - 5x2 - 2x - 9


Let me see if I can find your error

0- -6 is not -5 in your x^3
(edited 9 years ago)
Original post by TenOfThem
Let me see if I can find your error

0- -6 is not -5 in your x^3


surely,-6x3 + x3 = -5x3?
Original post by JamesNeedHelp2
surely,-6x3 + x3 = -5x3?


Well, yes, -6+1=-5

But you had 0 and needed to subtract -6 and 0--6 = 6
Original post by TenOfThem
Well, yes, -6+1=-5

But you had 0 and needed to subtract -6 and 0--6 = 6


aaaah i see, im so retarded. Appreciated.

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