College

Simplify the following expression:

[tex] (2x - 3)(5x^4 - 7x^3 + 6x^2 - 9) [/tex]

A. [tex] 10x^5 + 29x^4 - 33x^3 + 18x^2 + 18x - 27 [/tex]

B. [tex] 10x^5 + x^4 + 33x^3 + 18x^2 + 18x + 27 [/tex]

C. [tex] 10x^5 - x^4 - 9x^3 - 18x^2 - 18x - 27 [/tex]

D. [tex] 10x^5 - 29x^4 + 33x^3 - 18x^2 - 18x + 27 [/tex]

Answer :

To simplify
[tex]$$
(2x - 3)\left(5x^4 - 7x^3 + 6x^2 - 9\right),
$$[/tex]
we start by distributing each term in the binomial to every term in the polynomial.

1. Distribute the first term, [tex]$2x$[/tex], across the polynomial:
[tex]\[
\begin{aligned}
2x \cdot 5x^4 &= 10x^5, \\
2x \cdot (-7x^3) &= -14x^4, \\
2x \cdot 6x^2 &= 12x^3, \\
2x \cdot (-9) &= -18x.
\end{aligned}
\][/tex]

2. Distribute the second term, [tex]$-3$[/tex], across the polynomial:
[tex]\[
\begin{aligned}
-3 \cdot 5x^4 &= -15x^4, \\
-3 \cdot (-7x^3) &= 21x^3, \\
-3 \cdot 6x^2 &= -18x^2, \\
-3 \cdot (-9) &= 27.
\end{aligned}
\][/tex]

3. Now, combine like terms:
- For [tex]$x^5$[/tex]: The only term is [tex]$10x^5$[/tex].
- For [tex]$x^4$[/tex]: Combine [tex]$-14x^4$[/tex] and [tex]$-15x^4$[/tex] to get
[tex]$$
-14x^4 - 15x^4 = -29x^4.
$$[/tex]
- For [tex]$x^3$[/tex]: Combine [tex]$12x^3$[/tex] and [tex]$21x^3$[/tex] to get
[tex]$$
12x^3 + 21x^3 = 33x^3.
$$[/tex]
- For [tex]$x^2$[/tex]: The only term is [tex]$-18x^2$[/tex].
- For [tex]$x$[/tex]: The only term is [tex]$-18x$[/tex].
- The constant term is [tex]$27$[/tex].

4. Thus, the final expanded expression is:
[tex]$$
10x^5 - 29x^4 + 33x^3 - 18x^2 - 18x + 27.
$$[/tex]

This is the simplified form of the given expression.