Given:
The number of sandwich lunch specials sold is represented by [tex]\( x \)[/tex], and the number of wrap lunch specials sold is represented by [tex]\( y \)[/tex].

1. Change the equation into slope-intercept form. Identify the slope and [tex]\( y \)[/tex]-intercept of the equation. Be sure to show all your work below:
[tex]\[
\begin{array}{l}
3y = 1470 - 2x \\
y = \frac{1470}{3} - \frac{2x}{3} \\
y = 490 - \frac{2}{3}x \\
y = -\frac{2}{3}x + 490
\end{array}
\][/tex]

- The slope is [tex]\(-\frac{2}{3}\)[/tex], which is the coefficient of [tex]\( x \)[/tex].
- The [tex]\( y \)[/tex]-intercept is 490.
- The slope is approximately -0.67.

2. Describe how you would graph this line using the slope-intercept method. Be sure to write in complete sentences.



Answer :

Sure, let's work through this problem step-by-step.

1. Change the equation into slope-intercept form [tex]\(y = mx + b\)[/tex]:

[tex]\[ \begin{array}{l} 3y = 1470 - 2x \end{array} \][/tex]

First, solve for [tex]\(y\)[/tex] by isolating [tex]\(y\)[/tex] on one side of the equation:

[tex]\[ \begin{array}{l} 3y = 1470 - 2x \\ y = \frac{1470}{3} - \frac{2x}{3} \\ y = 490 - \frac{2}{3}x \end{array} \][/tex]

Rewriting it in the standard form [tex]\(y = mx + b\)[/tex], we get:

[tex]\[ y = -\frac{2}{3}x + 490 \][/tex]

From the final form of the equation [tex]\(y = mx + b\)[/tex], we identify:
- The slope ([tex]\(m\)[/tex]) is [tex]\(-\frac{2}{3}\)[/tex].
- The y-intercept ([tex]\(b\)[/tex]) is [tex]\(490\)[/tex].

2. Describe how to graph the line using the slope-intercept method:

To graph the line using the slope-intercept method, follow these steps:

- Step 1: Start by plotting the y-intercept. The y-intercept is the point where the line crosses the y-axis. In this case, the y-intercept [tex]\(b\)[/tex] is [tex]\(490\)[/tex]. So, plot the point [tex]\((0, 490)\)[/tex] on the graph.

- Step 2: Use the slope to determine the next point. The slope [tex]\(m\)[/tex] of [tex]\(-\frac{2}{3}\)[/tex] means that for every 3 units you move horizontally to the right (positive direction of [tex]\(x\)[/tex]), you move 2 units down (negative direction of [tex]\(y\)[/tex]). Conversely, for every 3 units you move to the left, you move 2 units up.

- From the point [tex]\((0, 490)\)[/tex], move 3 units to the right along the x-axis to [tex]\(x = 3\)[/tex], then move 2 units down along the y-axis to get to the point [tex]\((3, 488)\)[/tex].

- Alternatively, you can move 3 units to the left along the x-axis to [tex]\(x = -3\)[/tex], then move 2 units up along the y-axis to get to the point [tex]\((-3, 492)\)[/tex].

- Step 3: Plot these points on the graph and draw a straight line through them. Make sure the line extends across the entire graph.

By following these steps, you have correctly graphed the line using the slope-intercept method. The line will have a negative slope, gently decreasing from left to right, reflecting the slope of [tex]\(-\frac{2}{3}\)[/tex].