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

[tex]\[
\begin{array}{|c|c|}
\hline
x & f(x) \\
\hline
-4 & -17.2 \\
\hline
-2 & -13.6 \\
\hline
0 & -10 \\
\hline
2 & -6.4 \\
\hline
4 & -2.8 \\
\hline
\end{array}
\][/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 functions [tex]\(f(x) = 1.8x - 10\)[/tex] and [tex]\(g(x) = -4\)[/tex] equal to each other and solve for [tex]\(x\)[/tex].

The equation we need to solve is:
[tex]\[ 1.8x - 10 = -4 \][/tex]

Now, let's solve this equation step-by-step to find the value of [tex]\(x\)[/tex].

1. Add 10 to both sides:
[tex]\[ 1.8x - 10 + 10 = -4 + 10 \][/tex]
This simplifies to:
[tex]\[ 1.8x = 6 \][/tex]

2. Divide both sides by 1.8:
[tex]\[ x = \frac{6}{1.8} \][/tex]

Thus, the value of [tex]\(x\)[/tex] where [tex]\(f(x) = g(x)\)[/tex] is:
[tex]\[ x = 3.\overline{3} \][/tex]

Therefore, the correct equation and solution are:
[tex]\[ 1.8x - 10 = -4 \quad ; \quad x = \frac{10}{3} \][/tex]

So, the input value [tex]\(x\)[/tex] where [tex]\(f(x) = g(x)\)[/tex] is:
[tex]\[ x = \frac{10}{3} \approx 3.333\overline{3} \][/tex]

Hence, the correct option is:
[tex]\[ 1.8x - 10 = -4 ; x = \frac{10}{3} \][/tex]