College

Choose the correct simplification of [tex]$(6x - 5)(2x^2 - 3x - 6)$[/tex].

A. [tex]12x^3 + 28x^2 + 21x + 30[/tex]

B. [tex]12x^3 - 28x^2 - 21x + 30[/tex]

C. [tex]12x^3 + 28x^2 - 21x + 30[/tex]

D. [tex]12x^3 - 28x^2 - 21x - 30[/tex]

Answer :

We begin by expanding the product

[tex]$$
(6x-5)(2x^2-3x-6)
$$[/tex]

using the distributive property.

1. Multiply each term in the first factor by each term in the second factor:

- Multiply [tex]\(6x\)[/tex] by [tex]\(2x^2\)[/tex]:
[tex]$$
6x \cdot 2x^2 = 12x^3.
$$[/tex]

- Multiply [tex]\(6x\)[/tex] by [tex]\(-3x\)[/tex]:
[tex]$$
6x \cdot (-3x) = -18x^2.
$$[/tex]

- Multiply [tex]\(6x\)[/tex] by [tex]\(-6\)[/tex]:
[tex]$$
6x \cdot (-6) = -36x.
$$[/tex]

- Multiply [tex]\(-5\)[/tex] by [tex]\(2x^2\)[/tex]:
[tex]$$
-5 \cdot 2x^2 = -10x^2.
$$[/tex]

- Multiply [tex]\(-5\)[/tex] by [tex]\(-3x\)[/tex]:
[tex]$$
-5 \cdot (-3x) = 15x.
$$[/tex]

- Multiply [tex]\(-5\)[/tex] by [tex]\(-6\)[/tex]:
[tex]$$
-5 \cdot (-6) = 30.
$$[/tex]

2. Now, combine like terms:

- The [tex]\(x^3\)[/tex]-term:
[tex]$$
12x^3.
$$[/tex]

- Combine the [tex]\(x^2\)[/tex]-terms:
[tex]$$
-18x^2 - 10x^2 = -28x^2.
$$[/tex]

- Combine the [tex]\(x\)[/tex]-terms:
[tex]$$
-36x + 15x = -21x.
$$[/tex]

- The constant term remains:
[tex]$$
30.
$$[/tex]

So, the simplified expression is

[tex]$$
12x^3-28x^2-21x+30.
$$[/tex]

Therefore, the correct simplification is

[tex]$$
12x^3-28x^2-21x+30.
$$[/tex]