Factor –8x3 – 2x2 – 12x – 3 by grouping. What is the resulting expression?

(2x2 – 3)(4x + 1)
(–2x2 – 3)(–4x + 1)
(2x2 – 3)(–4x + 1)
(–2x2 – 3)(4x + 1)

1 answer

To factor the expression \(-8x^3 - 2x^2 - 12x - 3\) by grouping, we can follow these steps:

  1. Group the terms: We can group as follows: \((-8x^3 - 2x^2)\) and \((-12x - 3)\).

  2. Factor out the common terms in each group:

    • From the first group \(-8x^3 - 2x^2\), we can factor out \(-2x^2\): \[ -2x^2(4x + 1) \]
    • From the second group \(-12x - 3\), we can factor out \(-3\): \[ -3(4x + 1) \]
  3. Combine the factored groups: Now we have: \[ -2x^2(4x + 1) - 3(4x + 1) \]

    Notice that both terms contain the common factor \((4x + 1)\), which we can factor out: \[ (4x + 1)(-2x^2 - 3) \]

  4. Rearranging: We often prefer to write the polynomial in descending order. The expression can be rewritten to show it in a standard form: \[ (4x + 1)(-2x^2 - 3) \] Since we want a specific form where all terms are grouped, we multiply out the first term if necessary.

From these steps, the resulting expression after grouping and factoring is:

\[ (4x + 1)(-2x^2 - 3) \]

Comparing this to the answer choices, we can see: \[ (-2x^2 - 3)(4x + 1) \]

Thus, the correct answer from the choices is:

\[ \textbf{(–2x^2 – 3)(4x + 1)} \]