Select the correct answer.

Function [tex]h[/tex] is the product of functions [tex]f[/tex] and [tex]g[/tex].
[tex]\[
\begin{array}{l}
f(x) = 4x - 6 \\
g(x) = 5x + 9
\end{array}
\][/tex]

Which equation defines function [tex]h[/tex]?

A. [tex]h(x) = 20x^2 - 54[/tex]
B. [tex]h(x) = 20x - 54[/tex]
C. [tex]h(x) = 20x^2 + 3x - 54[/tex]
D. [tex]h(x) = 20x^2 + 6x - 54[/tex]



Answer :

To determine the correct equation defining the function [tex]\( h(x) \)[/tex], which is the product of functions [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex], follow these steps:

1. Recall the functions [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex]:
[tex]\[ f(x) = 4x - 6 \][/tex]
[tex]\[ g(x) = 5x + 9 \][/tex]

2. Form the product [tex]\( h(x) \)[/tex] by multiplying [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex]:
[tex]\[ h(x) = f(x) \cdot g(x) \][/tex]
[tex]\[ h(x) = (4x - 6)(5x + 9) \][/tex]

3. Expand the product using the distributive property (FOIL method):
[tex]\[ h(x) = (4x - 6)(5x + 9) \][/tex]
[tex]\[ = 4x \cdot 5x + 4x \cdot 9 - 6 \cdot 5x - 6 \cdot 9 \][/tex]

4. Calculate each term individually:
[tex]\[ 4x \cdot 5x = 20x^2 \][/tex]
[tex]\[ 4x \cdot 9 = 36x \][/tex]
[tex]\[ -6 \cdot 5x = -30x \][/tex]
[tex]\[ -6 \cdot 9 = -54 \][/tex]

5. Combine all the terms:
[tex]\[ h(x) = 20x^2 + 36x - 30x - 54 \][/tex]

6. Simplify the expression by combining like terms:
[tex]\[ 36x - 30x = 6x \][/tex]
[tex]\[ h(x) = 20x^2 + 6x - 54 \][/tex]

Thus, the equation that defines [tex]\( h(x) \)[/tex] is:
[tex]\[ h(x) = 20x^2 + 6x - 54 \][/tex]

Among the given choices, the correct answer is:

D. [tex]\( h(x) = 20x^2 + 6x - 54 \)[/tex]