Math Problem Statement

Find an equation for the line below.

Solution

To find the equation of the line shown in the graph, we need to determine its slope and y-intercept. The general equation for a line is:

y=mx+by = mx + b

where:

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

1. Identifying two points

From the graph, the line passes through two visible points:

  • Point A(0,4)A(0, 4), which is on the y-axis.
  • Point B(4,4)B(4, -4).

2. Calculating the slope (mm)

The slope is given by:

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

Using the points A(0,4)A(0, 4) and B(4,4)B(4, -4):

  • x1=0x_1 = 0, y1=4y_1 = 4
  • x2=4x_2 = 4, y2=4y_2 = -4

Substitute into the formula:

m=4440=84=2m = \frac{-4 - 4}{4 - 0} = \frac{-8}{4} = -2

Thus, the slope mm is 2-2.


3. Finding the y-intercept (bb)

The y-intercept is where x=0x = 0. From point A(0,4)A(0, 4), we see that b=4b = 4.


4. Writing the equation

Substitute m=2m = -2 and b=4b = 4 into the general equation y=mx+by = mx + b:

y=2x+4y = -2x + 4


Final Answer:

The equation of the line is:

y=2x+4y = -2x + 4

Let me know if you need further explanation or help plotting it step-by-step.


Related Questions:

  1. How do you determine the slope if you are given two points?
  2. What is the slope-intercept form of a linear equation?
  3. How can you rewrite a linear equation in standard form?
  4. How does the graph of a line change when the slope or intercept changes?
  5. What is the significance of the y-intercept?

Tip: The slope tells you the steepness and direction of the line. A negative slope means the line is slanting downwards from left to right.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Slope-Intercept Form

Formulas

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

Theorems

Slope-Intercept Form

Suitable Grade Level

Grades 8-10