Math Problem Statement

Write the equation of the line in fully simplified form

Write the equation of the line in fully simplified form.

Solution

To find the equation of the line shown in the image, we can use the slope-intercept form of a line equation:

y=mx+by = mx + b

Where:

  • mm is the slope of the line.
  • bb is the y-intercept (the point where the line crosses the y-axis).

Step 1: Determine the slope mm

To calculate the slope, we need two points on the line. From the graph, we can pick two points where the line crosses the grid neatly:

  • Point 1: (10,10)(-10, 10)
  • Point 2: (0,5)(0, 5)

The formula for the slope mm 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}

Substitute the points (10,10)(-10, 10) and (0,5)(0, 5):

m=5100(10)=510=12m = \frac{5 - 10}{0 - (-10)} = \frac{-5}{10} = -\frac{1}{2}

Step 2: Determine the y-intercept bb

From the graph, the line crosses the y-axis at y=5y = 5, so the y-intercept b=5b = 5.

Step 3: Write the equation

Now that we have the slope m=12m = -\frac{1}{2} and the y-intercept b=5b = 5, we can write the equation of the line:

y=12x+5y = -\frac{1}{2}x + 5

This is the fully simplified equation of the line.

Would you like more details or have any questions?

Here are 5 related questions to expand on this:

  1. How do you find the slope if the line is vertical?
  2. What is the meaning of a positive versus negative slope?
  3. How can you rewrite the equation of the line in point-slope form?
  4. How would the equation change if the line were steeper?
  5. What if the line passed through the origin—how would the equation be affected?

Tip: Always make sure to use points that lie exactly on the grid intersections when calculating slope from a graph for greater accuracy.

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Math Problem Analysis

Mathematical Concepts

Algebra
Coordinate Geometry

Formulas

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

Theorems

Slope-intercept form of a line

Suitable Grade Level

Grades 8-10