High School

What is the product of the polynomials below?

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

A. [tex]10x^3 + 28x^2 - 12x - 18[/tex]
B. [tex]10x^3 + 28x^2 - 12x - 3[/tex]
C. [tex]10x^3 + 28x^2 + 12x + 3[/tex]
D. [tex]10x^3 + 28x^2 + 12x + 18[/tex]

Answer :

To find the product of the polynomials [tex]\((5x^2 - x - 3)(2x + 6)\)[/tex], we'll use the distributive property (also known as the FOIL method when dealing with binomials). Here's the step-by-step process:

1. Distribute each term in the first polynomial to each term in the second polynomial:

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

2. Multiply each term:

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

[tex]\[
= 10x^3 + 30x^2 - 2x^2 - 6x - 6x - 18
\][/tex]

3. Combine like terms:

[tex]\[
= 10x^3 + (30x^2 - 2x^2) - (6x + 6x) - 18
\][/tex]

[tex]\[
= 10x^3 + 28x^2 - 12x - 18
\][/tex]

Thus, the product of the polynomials [tex]\( (5x^2 - x - 3)(2x + 6) \)[/tex] is [tex]\(\boldsymbol{10x^3 + 28x^2 - 12x - 18}\)[/tex].

So, the correct answer is:

A. [tex]\(10x^3 + 28x^2 - 12x - 18\)[/tex]