Gerri purchases a coupon book with discounts for her favorite coffee shop. Every coupon for the coffee shop offers the same discount. The table shows her total savings, [tex]$y$[/tex], based on the number of coupons, [tex]$x$[/tex], used from the book.

Coffee Shop Coupon Savings

[tex]\[
\begin{tabular}{|c|c|}
\hline
$x$ & $y$ \\
\hline
0 & -20 \\
\hline
5 & -10 \\
\hline
10 & 0 \\
\hline
15 & 10 \\
\hline
20 & 20 \\
\hline
\end{tabular}
\][/tex]

What are the slope and [tex]$y$[/tex]-intercept of the line represented by the points shown in the table?

A. slope: [tex]$2$[/tex], [tex]$y$[/tex]-intercept: -20
B. slope: [tex]$2$[/tex], [tex]$y$[/tex]-intercept: 10
C. slope: [tex]$5$[/tex], [tex]$y$[/tex]-intercept: -20
D. slope: [tex]$5$[/tex], [tex]$y$[/tex]-intercept: 10



Answer :

To find the slope and [tex]\( y \)[/tex]-intercept of the line represented by the points in the table, we need to follow these steps:

### Step 1: Understanding the Table
The given table shows the relationship between the number of coupons [tex]\( x \)[/tex] and the total savings [tex]\( y \)[/tex]:

[tex]\[ \begin{array}{|c|c|} \hline x & y \\ \hline 0 & -20 \\ \hline 5 & -10 \\ \hline 10 & 0 \\ \hline 15 & 10 \\ \hline 20 & 20 \\ \hline \end{array} \][/tex]

### Step 2: Calculate the Slope (m)
The slope [tex]\( m \)[/tex] of a line through two points [tex]\((x_1, y_1)\)[/tex] and [tex]\((x_2, y_2)\)[/tex] is calculated using the formula:

[tex]\[ m = \frac{y_2 - y_1}{x_2 - x_1} \][/tex]

We can choose any two points from the table for this calculation. Let's take the points (0, -20) and (5, -10).

Here, [tex]\( x_1 = 0 \)[/tex], [tex]\( y_1 = -20 \)[/tex], [tex]\( x_2 = 5 \)[/tex], and [tex]\( y_2 = -10 \)[/tex].

Using the formula:
[tex]\[ m = \frac{-10 - (-20)}{5 - 0} = \frac{-10 + 20}{5} = \frac{10}{5} = 2 \][/tex]

So, the slope [tex]\( m \)[/tex] is [tex]\( 2 \)[/tex].

### Step 3: Determine the y-intercept (b)
The [tex]\( y \)[/tex]-intercept [tex]\( b \)[/tex] is the point where the line crosses the [tex]\( y \)[/tex]-axis. This occurs when [tex]\( x = 0 \)[/tex].

From the table, when [tex]\( x = 0 \)[/tex], [tex]\( y = -20 \)[/tex]. Therefore, the [tex]\( y \)[/tex]-intercept [tex]\( b \)[/tex] is [tex]\( -20 \)[/tex].

### Final Answer
The slope and [tex]\( y \)[/tex]-intercept of the line represented by the points shown in the table are:
[tex]\[ \text{slope: } 2, \ y\text{-intercept: } -20 \][/tex]

This means the correct answer is:
[tex]\[ \text{slope: } 2, \ y\text{-intercept: } -20 \][/tex]