Math Problem Statement

Answer that show your solution and explanation

Graph and find the domain and range of the following functions: 1. f(x) = -4x + 12, 2. g(x) = -7, 3. h(x) = -4x^2 - 16x + 1, 4. r(x) = sqrt(-2x + 6), 5. f(x) = sqrt(3x + 12).

Solution

Let's break down and solve each of the five functions given in the worksheet. I'll also explain how to find the domain and range of each.

1. f(x)=4x+12f(x) = -4x + 12

This is a linear function, as it is in the form y=mx+by = mx + b, where mm is the slope and bb is the y-intercept.

  • Domain: A linear function has no restrictions, so the domain is all real numbers: (,)(-\infty, \infty).
  • Range: Since the function is linear and can take any real value as xx changes, the range is also (,)(-\infty, \infty).

To graph this, the slope m=4m = -4 means that for each unit increase in xx, yy decreases by 4. The y-intercept is 12, meaning the graph crosses the y-axis at (0,12)(0, 12).

2. g(x)=7g(x) = -7

This is a constant function.

  • Domain: Since it is defined for all xx, the domain is (,)(-\infty, \infty).
  • Range: The range is just the constant value g(x)=7g(x) = -7, so the range is {7}\{-7\}.

The graph is a horizontal line at y=7y = -7.

3. h(x)=4x216x+1h(x) = -4x^2 - 16x + 1

This is a quadratic function. To find the domain and range, we will need to analyze its vertex form. We can complete the square or use the vertex formula to find the vertex.

  • Domain: A quadratic function is defined for all real values of xx, so the domain is (,)(-\infty, \infty).

  • Range: The parabola opens downward (since the coefficient of x2x^2 is negative). To find the range, we need the vertex. The vertex formula is:

    x=b2a=(16)2(4)=168=2x = \frac{-b}{2a} = \frac{-(-16)}{2(-4)} = \frac{16}{-8} = -2

    Substituting x=2x = -2 back into the function to find the corresponding yy-value:

    h(2)=4(2)216(2)+1=4(4)+32+1=16+32+1=17h(-2) = -4(-2)^2 - 16(-2) + 1 = -4(4) + 32 + 1 = -16 + 32 + 1 = 17

    So the vertex is (2,17)(-2, 17), and since the parabola opens downward, the range is (,17](-\infty, 17].

4. r(x)=2x+6r(x) = \sqrt{-2x + 6}

This is a square root function. The expression inside the square root must be non-negative for the function to be defined.

  • Domain: We solve the inequality 2x+60-2x + 6 \geq 0:

    2x6x3-2x \geq -6 \quad \Rightarrow \quad x \leq 3

    So the domain is (,3](-\infty, 3].

  • Range: The square root function always produces non-negative outputs. Therefore, the range is [0,)[0, \infty).

5. f(x)=3x+12f(x) = \sqrt{3x + 12}

This is also a square root function. Again, the expression inside the square root must be non-negative.

  • Domain: Solve 3x+1203x + 12 \geq 0:

    3x12x43x \geq -12 \quad \Rightarrow \quad x \geq -4

    So the domain is [4,)[-4, \infty).

  • Range: Since the square root function yields non-negative values, the range is [0,)[0, \infty).


Let me know if you need any further clarifications, and here are five related questions you might want to explore further:

  1. How do you find the vertex of a quadratic function algebraically?
  2. What does the slope of a linear function represent geometrically?
  3. Why do square root functions have restricted domains and ranges?
  4. How would you graph a quadratic function by completing the square?
  5. How can transformations (like shifts and stretches) affect the graph of a square root function?

Tip: Always check if the function has any domain restrictions (like square roots or divisions) before finding its range.

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Math Problem Analysis

Mathematical Concepts

Linear Functions
Quadratic Functions
Square Root Functions
Domain and Range

Formulas

Linear function formula: y = mx + b
Quadratic function vertex formula: x = -b / 2a
Square root domain constraint: Expression inside square root ≥ 0

Theorems

Vertex Theorem for Quadratics
Properties of Linear Functions
Properties of Square Root Functions

Suitable Grade Level

Grades 9-12