Example

Factoring x3+27x^3 + 27

To factor the binomial x3+27x^3 + 27, we can apply the sum of cubes pattern, which is a3+b3=(a+b)(a2ab+b2)a^3 + b^3 = (a + b)(a^2 - ab + b^2).

Step 1: Verify that the binomial fits the pattern. The expression is a sum. The first term, x3x^3, is a perfect cube. The last term is 2727, which is also a perfect cube because 33=273^3 = 27. Therefore, this is a sum of two cubes.

Step 2: Rewrite the terms as cubes to identify the bases: a=xa = x and b=3b = 3. x3+27=x3+33x^3 + 27 = x^3 + 3^3

Step 3: Apply the sum of cubes pattern. Substitute xx and 33 into the formula: (x+3)(x2x3+32)(x + 3)(x^2 - x \cdot 3 + 3^2)

Step 4: Simplify the terms inside the trinomial factor: (x+3)(x23x+9)(x + 3)(x^2 - 3x + 9)

Step 5: Check the result by multiplying the binomial and the trinomial: (x+3)(x23x+9)=x(x23x+9)+3(x23x+9)(x + 3)(x^2 - 3x + 9) = x(x^2 - 3x + 9) + 3(x^2 - 3x + 9) =x33x2+9x+3x29x+27= x^3 - 3x^2 + 9x + 3x^2 - 9x + 27 =x3+27= x^3 + 27

The completely factored form is (x+3)(x23x+9)(x + 3)(x^2 - 3x + 9).

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Updated 2026-04-30

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