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7 answers

x^3+27
=(x)^3+(3)^3
=(x+3) {(x^2-x.3+(3)^2}
=(x+3)(x^2-3x+9)

2007-01-16 17:20:12 · answer #1 · answered by alpha 7 · 0 0

How to factor a sum of cubes:

1) Take the cube root of each term and place in the first set of brackets. In this case, we're going to have
(x + 3)

2) From these values, you're going to construct values in a second set of brackets, which goes as follows:
a) Square the first
b) Negative product
c) Square the last.

"Square the first"

For (x - 3), you want to square the first value of the brackets. Therefore, you square x, which is x^2.

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

"Negative product"

For the terms x and -3, take their product by multiplying them together (-3x), and then take their *negative* by multiplying by (-1). So you should get 3x.

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

"Square the last"

This means to square the second term in the first set of brackets. As you can see, (-3)^2 = 9, so we have

(x - 3) (x^2 + 3x + 9)

You have now successfully factored a sum of cubes. Difference of cubes works the exact same way.

2007-01-16 15:45:39 · answer #2 · answered by Puggy 7 · 0 0

do you mean x^3+27=0?
if so the answer is -3

2007-01-16 15:21:59 · answer #3 · answered by Anonymous · 0 0

Your statement doesn't have an assertion (like an "="), so it has no answer.

if x^3 +27 = 0, then x=-3

2007-01-16 15:22:56 · answer #4 · answered by Anonymous · 0 0

Factoring? This is the sum of two cubes:
(x+3)(x^2-3x+9)

2007-01-16 15:22:42 · answer #5 · answered by Professor Maddie 4 · 1 0

x^3+27=0
x^3=-27
x=3i
("i" is an imaginary # used as a substitute for negative 1

2007-01-16 16:53:05 · answer #6 · answered by Havanator 2 · 0 0

x3^3+27
27x+27
27x=-27
-1

2007-01-16 15:25:35 · answer #7 · answered by Micky [momo]♥ 2 · 0 3

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