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2007-01-03 13:24:16 · 10 answers · asked by tweety b 1 in Science & Mathematics Mathematics

10 answers

x³ - 3x² + 4x - 12

Notice that the ratio of the first two coefficients (1:-3) is the same as the ratio of the last two (4:-12 = 1:-3). Whenever this happens (or when the ratio of the 1st and 3rd is the same as the ratio of the 2nd and 4th), you will have a common factor.

Factor x² out of the first two, and 4 out of the last two:

x²(x - 3) + 4(x - 3)

Now you can factor (x + 3) out of both:

(x - 3)(x² + 4)

Since x² + 4 is not factorable (over the real numbers), that's as far as you can go.

If you're looking for complex roots too, then x² + 4 factors to x + 2i and x - 2i:

(x + 3)(x - 2i)(x + 2i)

2007-01-03 13:26:19 · answer #1 · answered by Jim Burnell 6 · 1 0

x^3-3x^2+4x-12 1 factor is x-3

x^2+4
(x-3)\x^3 - 3 x^2 + 4 x - 12
- ( x^3 - 3 x^2)
4 x - 12
4x -12
0

x^3-3x^2+4x-12=(x-3)(x^2+4) x^2+4 has no real factors
(x-3)(x+2i)(x-2i)

2007-01-03 22:25:00 · answer #2 · answered by yupchagee 7 · 0 0

x^3-3x^2+4x-12

Group the first two terms and the last two terms together.

x^3-3x^2 + 4x-12

Factor an x^2 out of the first group and a 4 out of the second group.

x^2(x-3) + 4(x-3)

Factor (x-3) out of both terms and your answer is:

(x-3)(x^2+4)

2007-01-03 21:29:01 · answer #3 · answered by vinnistelrooy 2 · 1 0

Looks like factor by grouping

x^2(x-3)+4(x-3)=(x^2+4)(x-3)

2007-01-03 21:26:38 · answer #4 · answered by christopher_az 2 · 1 0

x^3 - 3x^2 + 4x - 12
(x^2 + 4)(x - 3)

2007-01-03 21:28:28 · answer #5 · answered by Johnny Handsome 2 · 1 0

x^3-3x^2+4x-12 = (x-3)(x^2 + 4)

Now if you're not restricted to real factors..

x^3-3x^2+4x-12 = (x-3)(x+2i)(x-2i)

2007-01-03 21:32:44 · answer #6 · answered by The Alchemist 2 · 1 0

x^3-3x^2+4x-12
=x^2(x-3) +4(x-3)
=(x^2+4)(x-3)

2007-01-03 21:29:38 · answer #7 · answered by ironduke8159 7 · 1 0

x^2(x-3)+4(x-3)
(x^2+4)(x-3)

2007-01-03 21:53:25 · answer #8 · answered by Anonymous · 0 0

(x-3)(x^2+4)

Unfortunately, (x^2+4) can not be factored (using real numbers). It does, however, factor into (x+2i)(x-2i), using i (the square root of -1).

So the roots of the equation are 3 (the only real root) and 2i and -2i.

2007-01-03 21:33:30 · answer #9 · answered by actuator 5 · 1 0

x^3-3x^2+4x-12
(x^3-3x^2)+(4x-12)
x^2(x-3)+4(x-3)
(x^2+4)(x-3)
(x-2i)(x+2i)(x-3)
x= 2i, -2i and 3

2007-01-03 21:29:05 · answer #10 · answered by      7 · 1 0

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