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

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

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

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 \implies x = \frac{10}{3}[/tex]
B. [tex]1.8x = -4 \implies x = -\frac{20}{9}[/tex]
C. [tex]1.8x - 10 = -4 \implies 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 equations [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex] equal to each other. Given the functions:

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

Set these two equations equal to each other:

[tex]\[ 1.8x - 10 = -4 \][/tex]

Now solve for [tex]\( x \)[/tex]:

Step 1: Add 10 to both sides of the equation to isolate the term with [tex]\( x \)[/tex]:

[tex]\[ 1.8x - 10 + 10 = -4 + 10 \][/tex]
[tex]\[ 1.8x = 6 \][/tex]

Step 2: Divide by 1.8 to solve for [tex]\( x \)[/tex]:

[tex]\[ x = \frac{6}{1.8} \][/tex]

Simplifying this fraction:

[tex]\[ x = \frac{6}{1.8} = 3.\overline{3} \][/tex]

Therefore, the correct value of [tex]\( x \)[/tex] is:

[tex]\[ x = 3.\overline{3} \][/tex] or approximately [tex]\( x = 3.333 \)[/tex].

Among the given options, the correct equation that can be used to find the input value at which [tex]\( f(x) = g(x) \)[/tex] is:

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

However, note that [tex]\(\frac{10}{3}\)[/tex] is [tex]\( \approx 3.3333 \)[/tex], which matches our result. Thus, the correct solution is:

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