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
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answer #1
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answered by alpha 7
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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
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answer #2
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answered by Puggy 7
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do you mean x^3+27=0?
if so the answer is -3
2007-01-16 15:21:59
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answer #3
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answered by Anonymous
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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
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answer #4
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answered by Anonymous
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Factoring? This is the sum of two cubes:
(x+3)(x^2-3x+9)
2007-01-16 15:22:42
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answer #5
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answered by Professor Maddie 4
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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
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answer #6
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answered by Havanator 2
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x3^3+27
27x+27
27x=-27
-1
2007-01-16 15:25:35
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answer #7
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answered by Micky [momo]♥ 2
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