Answered

\begin{tabular}{|c|c|}
\hline
[tex]$x$[/tex] & [tex]$f(x)$[/tex] \\
\hline
-1 & -2 \\
\hline
2 & 4 \\
\hline
\end{tabular}

The table shown gives some values of [tex]$x$[/tex] and the corresponding values of [tex]$f(x)$[/tex], where [tex]$f$[/tex] is a linear function. If [tex]$y=f(x)$[/tex] is graphed in the [tex]$xy$[/tex]-plane, what is the [tex]$y$[/tex]-coordinate of the [tex]$y$[/tex]-intercept of the graph?

A) 1

B) 0.5

C) 0

D) -1



Answer :

To determine the [tex]\( y \)[/tex]-coordinate of the [tex]\( y \)[/tex]-intercept of the graph of [tex]\( y = f(x) \)[/tex], we need to follow these steps:

1. Identify the two given points: From the table, we know that the points are [tex]\((-1, -2)\)[/tex] and [tex]\( (2, 4) \)[/tex].

2. Calculate the slope ([tex]\( m \)[/tex]) of the linear function:
- The formula for the slope [tex]\( m \)[/tex] between two points [tex]\((x_1, f_1)\)[/tex] and [tex]\((x_2, f_2)\)[/tex] is:
[tex]\[ m = \frac{f_2 - f_1}{x_2 - x_1} \][/tex]
- Substituting the given points into the formula:
[tex]\[ m = \frac{4 - (-2)}{2 - (-1)} = \frac{4 + 2}{2 + 1} = \frac{6}{3} = 2 \][/tex]

3. Write the equation of the line in the form [tex]\( f(x) = mx + b \)[/tex]:
- We know the slope [tex]\( m = 2 \)[/tex] and we need to find the [tex]\( y \)[/tex]-intercept [tex]\( b \)[/tex].

4. Use one of the given points to solve for the [tex]\( y \)[/tex]-intercept [tex]\( b \)[/tex]:
- Using the point [tex]\((x_1, f_1) = (-1, -2)\)[/tex], substitute into the equation [tex]\( f(x) = mx + b \)[/tex]:
[tex]\[ -2 = 2(-1) + b \][/tex]
- Solve for [tex]\( b \)[/tex]:
[tex]\[ -2 = -2 + b \implies b = 0 \][/tex]

The [tex]\( y \)[/tex]-coordinate of the [tex]\( y \)[/tex]-intercept is [tex]\(\boxed{0}\)[/tex].