algebra · worked example

Solve x³ - 8

Method: difference of cubes. Verified step-by-step solution with our free AI math solver.
Problem

x38x^3 - 8

Step-by-step solution

  1. Recognise as difference of cubes: x38=x323x^3 - 8 = x^3 - 2^3.

  2. Apply the identity a3b3=(ab)(a2+ab+b2)a^3 - b^3 = (a - b)(a^2 + ab + b^2) with a=xa = x, b=2b = 2.

  3. Result: (x2)(x2+2x+4)(x - 2)(x^2 + 2x + 4).

  4. The trinomial factor x2+2x+4x^2 + 2x + 4 has discriminant 416=12<04 - 16 = -12 < 0, so it does not factor further over the reals.

Answer

(x2)(x2+2x+4)(x - 2)(x^2 + 2x + 4)

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