Math Problem Statement

Which equation correctly represents the line in slope-intercept form?

Solution

From the graph, we can see the line passing through points such as (4,8)(-4, 8), (2,3)(-2, 3), (0,2)(0, -2), and (2,7)(2, -7). To find the correct equation of this line in slope-intercept form y=mx+by = mx + b, we need to determine the slope (mm) and the y-intercept (bb).

Step 1: Calculate the slope (mm)

The formula for the slope between two points (x1,y1)(x_1, y_1) and (x2,y2)(x_2, y_2) is:

m=y2y1x2x1m = \frac{y_2 - y_1}{x_2 - x_1}

We can use any two points from the graph. Let's take (4,8)(-4, 8) and (0,2)(0, -2).

m=280(4)=104=52m = \frac{-2 - 8}{0 - (-4)} = \frac{-10}{4} = -\frac{5}{2}

So the slope of the line is 52-\frac{5}{2}.

Step 2: Find the y-intercept (bb)

The y-intercept is where the line crosses the y-axis, which is at the point (0,2)(0, -2). So the y-intercept bb is 2-2.

Step 3: Write the equation

Now that we know the slope is 52-\frac{5}{2} and the y-intercept is 2-2, the equation of the line is:

y=52x2y = -\frac{5}{2}x - 2

Conclusion

The correct equation of the line is:

y=52x2y = -\frac{5}{2}x - 2

So the correct answer is the second option: y=52x2y = -\frac{5}{2}x - 2.

Let me know if you'd like further clarification or have any more questions!


Here are some related questions for further exploration:

  1. How do you find the slope of a line from its graph?
  2. How can you identify the y-intercept of a line on a graph?
  3. How would the equation change if the slope were positive instead of negative?
  4. How do you graph a line when you know the slope and y-intercept?
  5. What are the differences between slope-intercept form and point-slope form?

Tip: When identifying the slope from a graph, make sure to count the rise and run between two points to determine the correct ratio.

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Slope-Intercept Form

Formulas

Slope formula: m = (y2 - y1) / (x2 - x1)
Slope-Intercept Form: y = mx + b

Theorems

Slope Formula
Graphing Linear Equations

Suitable Grade Level

Grades 7-9