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Factor –8x3 – 2x2 – 12x – 3 by grouping. What is the resulting expression? A. (2x2 – 3)(4x + 1) b. (–2x2 – 3)(–4x + 1) c. (2x2 – 3)(–4x + 1) d. (–2x2 – 3)(4x + 1)

2 Answers

3 votes
it's D
(–2x2 – 3)(4x + 1)
User Giograno
by
7.2k points
4 votes

Consider the polynomial
-8x^3 - 2x^2 - 12x - 3. You can group first two terms and second two terms:


-8x^3 - 2x^2 - 12x - 3= (-8x^3 - 2x^2 )+(- 12x - 3).

Find the common factors in both brackets:

  • in brackets
    (-8x^3 - 2x^2 ) the common factor is
    -2x^2;
  • in brackets
    (- 12x - 3) the common factor is
    -3.

Then rewrite the polynomial as


-8x^3 - 2x^2 - 12x - 3= (-8x^3 - 2x^2 )+(- 12x - 3) =-2x^2(4x+1)-3(4x+1).

Here you see that expression 4x+1 is common, then


-8x^3 - 2x^2 - 12x - 3=-2x^2(4x+1)-3(4x+1)=(4x+1)(-2x^2-3)..

Answer: correct choice is D.

User FrobberOfBits
by
8.0k points
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