Consider [tex]\( f(x) = 1.8x - 10 \)[/tex] and [tex]\( g(x) = -4 \)[/tex].

[tex]\[
\begin{tabular}{|c|c|}
\hline
x & f(x) \\
\hline
-4 & -17.2 \\
\hline
-2 & -13.6 \\
\hline
0 & -10 \\
\hline
2 & -6.4 \\
\hline
4 & -2.8 \\
\hline
\end{tabular}
\][/tex]

[tex]\[
\begin{tabular}{|c|c|}
\hline
x & g(x) \\
\hline
-4 & -4 \\
\hline
-2 & -4 \\
\hline
0 & -4 \\
\hline
2 & -4 \\
\hline
4 & -4 \\
\hline
\end{tabular}
\][/tex]

Select the equation that can be used to find the input value at which [tex]\( f(x) = g(x) \)[/tex], and then use that equation to find the input, or [tex]\( x \)[/tex]-value.

A. [tex]\( 1.8x - 10 = -4 \)[/tex]; [tex]\( x = \frac{10}{3} \)[/tex]

B. [tex]\( 1.8x = -4 \)[/tex]; [tex]\( x = -\frac{20}{9} \)[/tex]

C. [tex]\( 1.8x - 10 = -4 \)[/tex]; [tex]\( x = -\frac{10}{3} \)[/tex]

D. [tex]\( -4 = x \)[/tex]



Answer :

To find the input value [tex]\( x \)[/tex] at which [tex]\( f(x) = g(x) \)[/tex], we need to set the given functions equal to each other and solve for [tex]\( x \)[/tex].

Given:
[tex]\[ f(x) = 1.8x - 10 \][/tex]
[tex]\[ g(x) = -4 \][/tex]

Set [tex]\( f(x) \)[/tex] equal to [tex]\( g(x) \)[/tex]:
[tex]\[ 1.8x - 10 = -4 \][/tex]

Now, solve for [tex]\( x \)[/tex]:
1. Add 10 to both sides of the equation to isolate the term containing [tex]\( x \)[/tex]:
[tex]\[ 1.8x - 10 + 10 = -4 + 10 \][/tex]
[tex]\[ 1.8x = 6 \][/tex]

2. Divide both sides by 1.8 to solve for [tex]\( x \)[/tex]:
[tex]\[ x = \frac{6}{1.8} \][/tex]

3. Simplify the right-hand side:
[tex]\[ x = \frac{6}{1.8} = 3.333333333333333 \][/tex]

Therefore, the input value at which [tex]\( f(x) = g(x) \)[/tex] is approximately:
[tex]\[ x \approx 3.33 \][/tex]

Among the choices provided, the correct equation to find the input value is:
[tex]\[ 1.8x - 10 = -4 \][/tex]

This corresponds to the correct evaluation of:
[tex]\[ x = \frac{6}{1.8} = 3.33 \][/tex]