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Explanation: 27a to the 4th exponent minus a.

2007-09-07 06:29:38 · 10 answers · asked by nealee 2 in Science & Mathematics Mathematics

10 answers

27a^4 - a
= a(27a^3 - 1)
= a[(3^3)(a^3) - 1]
= a [(3a)^3 - 1]
= a (3a - 1)[(3a)^2 + (3a)(1) + 1^2]
= a (3a - 1) (9a^2 + 3a + 1)

Note:
Difference of Cubes formula:
a^3 - b^3
= (a - b)(a^2 + ab + b^2)

2007-09-07 06:34:04 · answer #1 · answered by Mathematica 7 · 1 0

Factor out a to get a* (27a^3-1). The term in ( )
has a difference of cubes solution, which I believe is (3a-1)(9a^2+9a+1). You might want to check this form in your book.

2007-09-07 06:37:26 · answer #2 · answered by cattbarf 7 · 0 0

OK, I will do this one eventhough yu got so many answers:

facor out an a to get:

a (27a³ - 1) =

now you have the diff of cubes:

a(3a -1)(9a² + 3a + 1)

2007-09-07 06:54:41 · answer #3 · answered by 037 G 6 · 0 0

1) look for common factors.

note you can factor out a, as
a(27a^3 - 1).

2) Look for special products, like A^3 - B^3. Note this is

(A-B)(A^2 + AB + B^2), so

a(27a^3 -1) = a( [3a]^3 - [1]^3), or A = 3a, B = 1 in formula
= a(3a-1)( [3a]^2 + [3a][1] + [1]^2) or
= a(3a-1)(9a^2 + 3a + 1)

2007-09-07 06:35:31 · answer #4 · answered by pbb1001 5 · 1 0

27a^4-a
a(27a^3-1)
a(3a-1)(.......? )
(....?...) is (9a^2+3a+1)
I got that by dividing (3a-1) into (27a^3-1). I was careful to write this as (27a^3+0a^2+0a-1) /(3a-1)
I don't know how you like to do this kind of division, so I leave this detail to you. However you do it, your answer should be (9a^2+3a+1), the same as mine.

The final answer is 27a^4-a =a(3a-1)(9a^2+3a+1)

2007-09-07 06:41:40 · answer #5 · answered by Grampedo 7 · 0 0

27a^4 - a=a(27a^3-1)
=a(3a-1)(9a^2+3a+1)

2007-09-07 06:41:57 · answer #6 · answered by Anonymous · 0 0

27a^4-a
=a[27a^3-1]
=a[(3a)^3- 1^3]
=a(3a-1)[9a^2+3a+1]. ANS.

2007-09-07 06:35:22 · answer #7 · answered by Anonymous · 0 0

take out one "a"

a(27a^3-1)

2007-09-07 06:33:47 · answer #8 · answered by Anonymous · 1 1

a*(3*a-1)*(9*a^2+3*a+1)

2007-09-07 06:37:01 · answer #9 · answered by ? 5 · 0 1

Go to www.webmath.com they have a great little section that does the factor and shows you the steps

2007-09-07 06:33:39 · answer #10 · answered by Mike B 2 · 1 1

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