Math Problem Statement

Determine the slope and y-intercept from a graph and several linear equations.

Solution

Let's walk through the answers for the slope-intercept form questions on the worksheet.

1. First Graph:

The slope-intercept form is given by the equation: y=mx+by = mx + b Where:

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

From the graph:

  • The slope (mm) is the change in yy divided by the change in xx between two points on the line. Let's take two points from the graph: (0, 3) and (2, 0).

    • From (0, 3) to (2, 0), the change in yy is 03=30 - 3 = -3, and the change in xx is 20=22 - 0 = 2.
    • So, the slope m=32=32m = \frac{-3}{2} = -\frac{3}{2}.
  • The y-intercept (bb) is the point where the line crosses the y-axis. From the graph, it crosses at (0,3)(0, 3), so b=3b = 3.

  • The x-intercept is the point where the line crosses the x-axis, which from the graph is (2,0)(2, 0).

Thus, the equation of the line is: y=32x+3y = -\frac{3}{2}x + 3

2. Table:

For each equation in the table, let's find the slope (mm) and the y-intercept (bb).

  1. y=2x+5y = 2x + 5:

    • Slope (mm) = 2
    • Y-intercept (bb) = 5
  2. y=x3y = -x - 3:

    • Slope (mm) = -1 (since x-x is equivalent to 1x-1x)
    • Y-intercept (bb) = -3
  3. y=7y = 7:

    • This is a horizontal line where y=7y = 7 for all xx, so the slope (mm) = 0.
    • Y-intercept (bb) = 7
  4. y=xy = -x:

    • Slope (mm) = -1
    • Y-intercept (bb) = 0 (since no constant is added, b=0b = 0)

Let me know if you'd like any further details or clarifications.

Follow-up questions:

  1. How can you identify the slope from an equation in slope-intercept form?
  2. What does the y-intercept tell you about a graph?
  3. How do you determine the x-intercept from a graph?
  4. What happens to the graph when the slope is positive versus negative?
  5. Can you have a slope with a zero y-intercept? What would it look like?

Tip:

To find the slope from a graph, always pick two clear points on the line and use the formula slope=ΔyΔx\text{slope} = \frac{\Delta y}{\Delta x}.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Slope-Intercept Form

Formulas

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

Theorems

Slope-Intercept Theorem

Suitable Grade Level

Grades 8-10