High School

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 :

To simplify the expression [tex]\((6x - 5)(2x^2 - 3x - 6)\)[/tex], follow these steps:

1. Distribute Each Term:

First, distribute [tex]\(6x\)[/tex] to each term in the second polynomial [tex]\(2x^2 - 3x - 6\)[/tex]:

- [tex]\(6x \cdot 2x^2 = 12x^3\)[/tex]
- [tex]\(6x \cdot (-3x) = -18x^2\)[/tex]
- [tex]\(6x \cdot (-6) = -36x\)[/tex]

So, [tex]\(6x(2x^2 - 3x - 6) = 12x^3 - 18x^2 - 36x\)[/tex].

2. Distribute [tex]\(-5\)[/tex] to Each Term:

Next, distribute [tex]\(-5\)[/tex] to each term in the second polynomial:

- [tex]\(-5 \cdot 2x^2 = -10x^2\)[/tex]
- [tex]\(-5 \cdot (-3x) = 15x\)[/tex]
- [tex]\(-5 \cdot (-6) = 30\)[/tex]

So, [tex]\(-5(2x^2 - 3x - 6) = -10x^2 + 15x + 30\)[/tex].

3. Combine the Results:

Now, add together the results from step 1 and step 2:

[tex]\[
(12x^3 - 18x^2 - 36x) + (-10x^2 + 15x + 30)
\][/tex]

- The [tex]\(x^3\)[/tex] term: [tex]\(12x^3\)[/tex].
- The [tex]\(x^2\)[/tex] terms: [tex]\(-18x^2 - 10x^2 = -28x^2\)[/tex].
- The [tex]\(x\)[/tex] terms: [tex]\(-36x + 15x = -21x\)[/tex].
- The constant term: [tex]\(30\)[/tex].

Thus, the simplified expression is:

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

Therefore, the correct simplification is [tex]\(\boxed{12x^3 - 28x^2 - 21x + 30}\)[/tex].