Math Problem Statement

Work out the equation of the line below using the points (-5, -5), (-2, -2), (3, 3), and (7, 7).

Solution

The image shows a graph with the equation of a line passing through several points, including (-5, -5), (-2, -2), (3, 3), and (7, 7). To find the equation of the line, we can use the slope-intercept form of a linear equation:

y=mx+by = mx + b

where:

  • mm is the slope,
  • bb is the y-intercept.

Step 1: Find the Slope mm

The slope mm is calculated as:

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

Using the points (7,7)(7,7) and (3,3)(3,3):

m=7373=44=1m = \frac{7 - 3}{7 - 3} = \frac{4}{4} = 1

Thus, the slope m=1m = 1.

Step 2: Find the y-intercept bb

Now, substitute the slope m=1m = 1 into the equation y=mx+by = mx + b, and use any point on the line to solve for bb. Let’s use the point (3,3)(3,3):

3=1(3)+b3 = 1(3) + b 3=3+b3 = 3 + b b=0b = 0

Final Equation

Thus, the equation of the line is:

y=xy = x

This means the line has a slope of 1 and passes through the origin (0,0).

Would you like more details on any step, or do you have further questions?


Here are 5 related questions to expand on this:

  1. What happens if we choose different points to calculate the slope?
  2. How can we verify that the line passes through the origin?
  3. What does the slope of a line represent in general?
  4. How would the equation change if the y-intercept were not 0?
  5. How do we calculate the slope of a vertical or horizontal line?

Tip: Always verify the line’s slope by selecting two distinct points on the graph to ensure consistency.

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Equations of Lines

Formulas

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

Theorems

Slope formula
Linear equation theorem

Suitable Grade Level

Grades 8-10