Which of the following represents the factorization of the trinomial below?
- 4x3 - 4x2 +24 x
O A. -4(x2-2)(x+3)
B. -4(x2 + 2)(x+3)
O C. -4x(x + 2)(x+3)
D. -4x(x - 2)(x+3)

Respuesta :

Answer:

D. -4x(x - 2)(x+3)

Step-by-step explanation:

We are given the following trinomial:

[tex]-4x^3 - 4x^2 + 24x[/tex]

-4x is the common term, so:

[tex]-4x(\frac{-4x^3}{-4x} - \frac{4x^2}{-4x^3} + \frac{24x}{-4x}) = -4x(x^2+x-6)[/tex]

The second degree polynomial can also be factored, finding it's roots.

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

[tex]ax^{2} + bx + c, a\neq0[/tex].

This polynomial has roots [tex]x_{1}, x_{2}[/tex] such that [tex]ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})[/tex], given by the following formulas:

[tex]x_{1} = \frac{-b + \sqrt{\Delta}}{2*a}[/tex]

[tex]x_{2} = \frac{-b - \sqrt{\Delta}}{2*a}[/tex]

[tex]\Delta = b^{2} - 4ac[/tex]

x² + x - 6

Quadratic equation with [tex]a = 1, b = 1, c = -6[/tex]

So

[tex]\Delta = 1^{2} - 4(1)(-6) = 25[/tex]

[tex]x_{1} = \frac{-1 + \sqrt{25}}{2} = 2[/tex]

[tex]x_{2} = \frac{-1 - \sqrt{25}}{2} = -3[/tex]

So

[tex]x^2 + x - 6 = (x - 2)(x - (-3)) = (x - 2)(x + 3)[/tex]

The complete factorization is:

[tex]-4x(x^2+x-6) = -4x(x - 2)(x + 3)[/tex]

Thus the correct answer is given by option d.