Math Problem Statement

Give two ways you can tell that the rule y = 2x - 3 does not match the graph shown.

Solution

To address the question in the uploaded image:

Part (a): Identifying Why y=2x3y = 2x - 3 Does Not Match the Graph

  1. Slope Mismatch: The rule y=2x3y = 2x - 3 has a slope of 2, meaning it rises 2 units for every 1 unit it moves to the right. However, the graph shown has a negative slope (it decreases as xx increases), indicating the slope in the equation does not match the graph's slope.
  2. Y-Intercept Mismatch: The rule y=2x3y = 2x - 3 has a y-intercept of 3-3 (where yy-value is 3-3 when x=0x = 0). The graph's y-intercept is at y=4y = 4, so the intercept in the equation does not match the graph.

Part (b): Alternative Rule Matching the Graph

To find an alternative rule:

  1. Identify the Slope: From the graph, the slope can be calculated. For every decrease of 4 units in yy, xx increases by 4 units, so the slope is: slope=44=1\text{slope} = \frac{-4}{4} = -1
  2. Identify the Y-Intercept: The graph intersects the y-axis at y=4y = 4. Hence, the y-intercept is 4.

The rule matching the graph is: y=x+4y = -x + 4

Would you like more details or have additional questions?

Related Questions:

  1. How do you calculate the slope of a line given two points on the graph?
  2. Can a line's equation be written in forms other than slope-intercept form? If so, how?
  3. What is the effect of changing the slope in a linear equation on the graph?
  4. How does altering the y-intercept in a linear equation affect its position on the graph?
  5. What techniques are useful for determining if a point lies on a given line?

Tip:

When examining graphs and equations, always match the slope and y-intercept to confirm correspondence.

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Graphing
Slope-Intercept Form

Formulas

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

Theorems

Slope-Intercept Theorem

Suitable Grade Level

Grades 7-9