Math Problem Statement

Sketch the following linear function using DESMOS: f(x) = (2/3)x + 4. Analyze the graph by answering the following questions: a) State the integer coordinates of the y-intercept. b) State the integer coordinates of the x-intercept. c) State the interval for x representing the mathematical domain. d) State the interval for y representing the mathematical range. e) Is the function increasing or decreasing on its domain?

Solution

Let's analyze the linear function f(x)=23x+4f(x) = \frac{2}{3}x + 4 and answer the questions from the image.

a) Integer coordinates of the y-intercept

The y-intercept occurs when x=0x = 0. Substituting x=0x = 0 into the equation:

f(0)=23(0)+4=4f(0) = \frac{2}{3}(0) + 4 = 4

So, the y-intercept is (0,4)(0, 4).

b) Integer coordinates of the x-intercept

The x-intercept occurs when f(x)=0f(x) = 0. Set the function equal to 0 and solve for xx:

0=23x+40 = \frac{2}{3}x + 4 23x=4\frac{2}{3}x = -4 x=4×32=6x = -4 \times \frac{3}{2} = -6

So, the x-intercept is (6,0)(-6, 0).

c) Domain of the function

The function is a linear function, which means it is defined for all real values of xx. Therefore, the domain is:

(,)(-\infty, \infty)

d) Range of the function

Since the function is linear and its graph is a straight line that extends infinitely in both directions, the range is also all real values:

(,)(-\infty, \infty)

e) Is the function increasing or decreasing?

The slope of the function is 23\frac{2}{3}, which is positive. This means the function is increasing on its domain.


Would you like any further details or explanations? Here are five related questions you might want to explore:

  1. How do you graph linear functions on DESMOS?
  2. What is the effect of the slope on the steepness of a linear graph?
  3. How do you find the slope of a line given two points?
  4. How do domain and range differ for different types of functions?
  5. How does the behavior of a function change if the slope is negative?

Tip: Always check the sign of the slope to determine if a function is increasing or decreasing. A positive slope means the function increases, while a negative slope means it decreases.

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Math Problem Analysis

Mathematical Concepts

Linear Functions
Intercepts
Domain and Range
Graph Analysis

Formulas

Slope-intercept form: y = mx + b
Y-intercept: occurs when x = 0
X-intercept: occurs when y = 0

Theorems

Linear functions have a constant rate of change, represented by their slope.

Suitable Grade Level

Grades 9-11