Math Problem Statement

Write an equation for a linear function given a graph of f(x) shown below.

Solution

To find the equation of the line, we use the slope-intercept form of a linear equation:

f(x)=mx+bf(x) = mx + b

Here:

  • mm is the slope of the line,
  • bb is the yy-intercept.

Step 1: Find the slope mm

To calculate the slope, use the formula:

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

From the graph:

  • One point on the line is (1,0)(-1, 0) (the yy-intercept).
  • Another point is (0,2)(0, -2).

Substitute into the slope formula:

m=200(1)=21=2m = \frac{-2 - 0}{0 - (-1)} = \frac{-2}{1} = -2

So, the slope mm is 2-2.


Step 2: Identify the yy-intercept bb

From the graph, the line crosses the yy-axis at b=2b = -2.


Step 3: Write the equation

Substitute m=2m = -2 and b=2b = -2 into the slope-intercept form:

f(x)=2x2f(x) = -2x - 2


Final Answer:

The equation of the line is:

f(x)=2x2f(x) = -2x - 2


Would you like a step-by-step explanation of how to calculate the slope or intercept in detail?

Here are some related questions to practice:

  1. How do you determine the slope if the two points are given explicitly?
  2. How can you write a line's equation if the slope and a point are given?
  3. What is the general formula for a line passing through two given points?
  4. How does changing the slope mm affect the line's graph?
  5. How do you find the equation of a vertical or horizontal line?

Tip: Remember, the slope mm tells you how steep the line is. A negative slope makes the line slant downwards from left to right.

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Slope-Intercept Form
Graphing

Formulas

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

Theorems

Slope-Intercept Theorem

Suitable Grade Level

Grades 8-10