Select The Quadratic Function With A Graph That Has The Following Features:- $x$-intercept At $(8,0)$- $y$-intercept At $(0,-32)$- Maximum Value At $(6,4)$- Axis Of Symmetry At $x=6$A.

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Understanding Quadratic Functions


Quadratic functions are a type of polynomial function that can be written in the form of f(x)=ax2+bx+cf(x) = ax^2 + bx + c, where aa, bb, and cc are constants. These functions have a parabolic shape and can have various features such as xx-intercepts, yy-intercepts, maximum or minimum values, and an axis of symmetry. In this article, we will discuss how to select the quadratic function with a graph that has specific features.

Features of the Graph


The graph of a quadratic function can have several features, including:

  • xx-intercept: The point where the graph intersects the xx-axis. This occurs when y=0y = 0.
  • yy-intercept: The point where the graph intersects the yy-axis. This occurs when x=0x = 0.
  • Maximum or minimum value: The highest or lowest point on the graph.
  • Axis of symmetry: A vertical line that passes through the maximum or minimum value and divides the graph into two symmetrical parts.

Given Features


The given features of the graph are:

  • xx-intercept at (8,0)(8,0): This means that the graph intersects the xx-axis at the point (8,0)(8,0).
  • yy-intercept at (0,โˆ’32)(0,-32): This means that the graph intersects the yy-axis at the point (0,โˆ’32)(0,-32).
  • Maximum value at (6,4)(6,4): This means that the highest point on the graph is at the point (6,4)(6,4).
  • Axis of symmetry at x=6x=6: This means that the vertical line x=6x=6 passes through the maximum value and divides the graph into two symmetrical parts.

Selecting the Quadratic Function


To select the quadratic function with a graph that has the given features, we need to use the following steps:

Step 1: Write the General Form of the Quadratic Function


The general form of a quadratic function is f(x)=ax2+bx+cf(x) = ax^2 + bx + c. We can start by writing this function in the general form.

Step 2: Use the xx-intercept to Find the Value of cc


The xx-intercept is the point where the graph intersects the xx-axis. This occurs when y=0y = 0. We can substitute the xx-intercept into the general form of the function to find the value of cc.

Step 3: Use the yy-intercept to Find the Value of aa


The yy-intercept is the point where the graph intersects the yy-axis. This occurs when x=0x = 0. We can substitute the yy-intercept into the general form of the function to find the value of aa.

Step 4: Use the Maximum Value to Find the Value of bb


The maximum value is the highest point on the graph. We can use this point to find the value of bb.

Step 5: Use the Axis of Symmetry to Find the Value of aa and bb


The axis of symmetry is a vertical line that passes through the maximum value and divides the graph into two symmetrical parts. We can use this line to find the values of aa and bb.

Solving for aa, bb, and cc


Let's solve for aa, bb, and cc using the given features.

Step 1: Write the General Form of the Quadratic Function


f(x)=ax2+bx+cf(x) = ax^2 + bx + c

Step 2: Use the xx-intercept to Find the Value of cc


The xx-intercept is (8,0)(8,0). We can substitute this point into the general form of the function to find the value of cc.

0=a(8)2+b(8)+c0 = a(8)^2 + b(8) + c

0=64a+8b+c0 = 64a + 8b + c

Step 3: Use the yy-intercept to Find the Value of aa


The yy-intercept is (0,โˆ’32)(0,-32). We can substitute this point into the general form of the function to find the value of aa.

โˆ’32=a(0)2+b(0)+c-32 = a(0)^2 + b(0) + c

โˆ’32=c-32 = c

Step 4: Use the Maximum Value to Find the Value of bb


The maximum value is (6,4)(6,4). We can use this point to find the value of bb.

4=a(6)2+b(6)โˆ’324 = a(6)^2 + b(6) - 32

4=36a+6bโˆ’324 = 36a + 6b - 32

36a+6b=3636a + 6b = 36

Step 5: Use the Axis of Symmetry to Find the Value of aa and bb


The axis of symmetry is x=6x=6. We can use this line to find the values of aa and bb.

Since the axis of symmetry is x=6x=6, we know that the vertex of the parabola is at the point (6,4)(6,4). We can use this information to find the values of aa and bb.

The vertex form of a quadratic function is f(x)=a(xโˆ’h)2+kf(x) = a(x-h)^2 + k, where (h,k)(h,k) is the vertex of the parabola. We can substitute the vertex into this form to find the values of aa and bb.

f(x)=a(xโˆ’6)2+4f(x) = a(x-6)^2 + 4

We can expand this expression to find the values of aa and bb.

f(x)=a(x2โˆ’12x+36)+4f(x) = a(x^2 - 12x + 36) + 4

f(x)=ax2โˆ’12ax+36a+4f(x) = ax^2 - 12ax + 36a + 4

We can compare this expression to the general form of the quadratic function to find the values of aa and bb.

ax2+bx+c=ax2โˆ’12ax+36a+4ax^2 + bx + c = ax^2 - 12ax + 36a + 4

We can equate the coefficients of the two expressions to find the values of aa and bb.

a=aa = a

โˆ’12a=b-12a = b

36a+4=c36a + 4 = c

We can solve for aa, bb, and cc using these equations.

Solving for aa


We can solve for aa using the equation 36a+4=c36a + 4 = c.

36a+4=โˆ’3236a + 4 = -32

36a=โˆ’3636a = -36

a=โˆ’1a = -1

Solving for bb


We can solve for bb using the equation โˆ’12a=b-12a = b.

โˆ’12a=b-12a = b

โˆ’12(โˆ’1)=b-12(-1) = b

b=12b = 12

Solving for cc


We can solve for cc using the equation 36a+4=c36a + 4 = c.

36a+4=c36a + 4 = c

36(โˆ’1)+4=c36(-1) + 4 = c

c=โˆ’32c = -32

The Quadratic Function


We can now substitute the values of aa, bb, and cc into the general form of the quadratic function to find the final answer.

f(x)=ax2+bx+cf(x) = ax^2 + bx + c

f(x)=โˆ’x2+12xโˆ’32f(x) = -x^2 + 12x - 32

The final answer is โˆ’x2+12xโˆ’32\boxed{-x^2 + 12x - 32}.

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Understanding Quadratic Functions


Quadratic functions are a type of polynomial function that can be written in the form of f(x)=ax2+bx+cf(x) = ax^2 + bx + c, where aa, bb, and cc are constants. These functions have a parabolic shape and can have various features such as xx-intercepts, yy-intercepts, maximum or minimum values, and an axis of symmetry.

Frequently Asked Questions


Q: What is a quadratic function?


A quadratic function is a type of polynomial function that can be written in the form of f(x)=ax2+bx+cf(x) = ax^2 + bx + c, where aa, bb, and cc are constants.

Q: What are the features of a quadratic function?


The features of a quadratic function include:

  • xx-intercept: The point where the graph intersects the xx-axis. This occurs when y=0y = 0.
  • yy-intercept: The point where the graph intersects the yy-axis. This occurs when x=0x = 0.
  • Maximum or minimum value: The highest or lowest point on the graph.
  • Axis of symmetry: A vertical line that passes through the maximum or minimum value and divides the graph into two symmetrical parts.

Q: How do I find the value of aa, bb, and cc in a quadratic function?


To find the value of aa, bb, and cc in a quadratic function, you can use the following steps:

  1. Use the xx-intercept to find the value of cc: Substitute the xx-intercept into the general form of the function to find the value of cc.
  2. Use the yy-intercept to find the value of aa: Substitute the yy-intercept into the general form of the function to find the value of aa.
  3. Use the maximum or minimum value to find the value of bb: Use the maximum or minimum value to find the value of bb.
  4. Use the axis of symmetry to find the value of aa and bb: Use the axis of symmetry to find the values of aa and bb.

Q: How do I write a quadratic function in vertex form?


To write a quadratic function in vertex form, you can use the following steps:

  1. Identify the vertex: Identify the vertex of the parabola, which is the point (h,k)(h,k).
  2. Write the function in vertex form: Write the function in the form f(x)=a(xโˆ’h)2+kf(x) = a(x-h)^2 + k, where (h,k)(h,k) is the vertex.

Q: How do I find the axis of symmetry of a quadratic function?


To find the axis of symmetry of a quadratic function, you can use the following steps:

  1. Identify the vertex: Identify the vertex of the parabola, which is the point (h,k)(h,k).
  2. Write the function in vertex form: Write the function in the form f(x)=a(xโˆ’h)2+kf(x) = a(x-h)^2 + k, where (h,k)(h,k) is the vertex.
  3. Find the axis of symmetry: The axis of symmetry is the vertical line x=hx=h.

Q: How do I find the maximum or minimum value of a quadratic function?


To find the maximum or minimum value of a quadratic function, you can use the following steps:

  1. Identify the vertex: Identify the vertex of the parabola, which is the point (h,k)(h,k).
  2. Write the function in vertex form: Write the function in the form f(x)=a(xโˆ’h)2+kf(x) = a(x-h)^2 + k, where (h,k)(h,k) is the vertex.
  3. Find the maximum or minimum value: The maximum or minimum value is the point (h,k)(h,k).

Conclusion


Quadratic functions are a type of polynomial function that can be written in the form of f(x)=ax2+bx+cf(x) = ax^2 + bx + c, where aa, bb, and cc are constants. These functions have a parabolic shape and can have various features such as xx-intercepts, yy-intercepts, maximum or minimum values, and an axis of symmetry. By understanding the features of a quadratic function and how to find the values of aa, bb, and cc, you can solve problems involving quadratic functions and write them in vertex form.

Additional Resources


  • Quadratic Function Formula: f(x)=ax2+bx+cf(x) = ax^2 + bx + c
  • Vertex Form of a Quadratic Function: f(x)=a(xโˆ’h)2+kf(x) = a(x-h)^2 + k
  • Axis of Symmetry: x=hx=h
  • Maximum or Minimum Value: (h,k)(h,k)

Practice Problems


  1. Find the value of aa, bb, and cc in the quadratic function f(x)=ax2+bx+cf(x) = ax^2 + bx + c given that the xx-intercept is (8,0)(8,0), the yy-intercept is (0,โˆ’32)(0,-32), and the maximum value is (6,4)(6,4).
  2. Write the quadratic function f(x)=ax2+bx+cf(x) = ax^2 + bx + c in vertex form given that the vertex is (h,k)(h,k).
  3. Find the axis of symmetry of the quadratic function f(x)=ax2+bx+cf(x) = ax^2 + bx + c given that the vertex is (h,k)(h,k).
  4. Find the maximum or minimum value of the quadratic function f(x)=ax2+bx+cf(x) = ax^2 + bx + c given that the vertex is (h,k)(h,k).