Math Problem Statement
Use the vertex and intercepts to sketch the graph of the quadratic function. Give the equation for the parabola's axis of symmetry. Use the graph to determine the function's domain and range.
f(x)equals=6 x squared plus 12 x minus 56x2+12x−5
Question content area bottom
Part 1
What is the vertex?
enter your response here
(Type an ordered pair.)
Part 2
What are the x-intercepts?
enter your response here
(Type an ordered pair. Use a comma to separate answers as needed. Round to the nearest hundredth as needed.)
Part 3
What is the y-intercept?
enter your response here
(Type an ordered pair.)
Part 4
Graph the quadratic function. Choose the correct graph below.
A.
-55-2010xy
A coordinate system has a horizontal x-axis labeled from negative 5 to 5 in increments of 1 and a vertical y-axis labeled from negative 20 to 10 in increments of 2. A parabola that opens upward has vertex (1, negative 11) and passes through the y-axis at (0, negative 5).
B.
-55-1020xy
A coordinate system has a horizontal x-axis labeled from negative 5 to 5 in increments of 1 and a vertical y-axis labeled from negative 10 to 20 in increments of 2. A parabola that opens downward has vertex (1, 11) and passes through the y-axis at (0, 5).
C.
-55-1020xy
A coordinate system has a horizontal x-axis labeled from negative 5 to 5 in increments of 1 and a vertical y-axis labeled from negative 10 to 20 in increments of 2. A parabola that opens downward has vertex (negative 1,11) and passes through the y-axis at (0, 5).
Solution
To solve this question and provide answers for each part step-by-step:
Part 1: Find the vertex
The function is given as:
The vertex form of a quadratic equation is:
where is the vertex.
To find the vertex, we use the formula for the x-coordinate of the vertex:
Here, , , and .
Substitute into the formula:
Now substitute into the original function to find the y-coordinate ():
Thus, the vertex is:
Part 2: Find the x-intercepts
To find the x-intercepts, set :
This is a standard quadratic equation, so we solve using the quadratic formula:
Substitute , , and :
Simplify :
Now compute the two roots:
- First root:
- Second root:
Thus, the x-intercepts are approximately:
Part 3: Find the y-intercept
The y-intercept occurs when . Substitute into :
Thus, the y-intercept is:
Part 4: Axis of symmetry
The axis of symmetry is the vertical line that passes through the vertex. Since the vertex is , the axis of symmetry is:
Part 5: Domain and Range
-
Domain: Since this is a quadratic function, the domain is all real numbers:
-
Range: The parabola opens upward (since ), so the minimum value of the function occurs at the vertex. The y-coordinate of the vertex is , so the range is:
Part 6: Correct graph
The parabola has:
- Vertex:
- Y-intercept:
- X-intercepts: and
From the options provided, Graph A is correct because:
- The parabola opens upward.
- The vertex is .
- The y-intercept matches .
Final Answers:
- Vertex:
- X-intercepts:
- Y-intercept:
- Axis of symmetry:
- Domain:
- Range:
Relative Questions:
- What does the direction of the parabola depend on in a quadratic equation?
- How do you determine the vertex of a quadratic function from standard form?
- What role does the axis of symmetry play in graphing a parabola?
- How do you find the y-intercept of a function algebraically?
- How can you verify the solutions of a quadratic equation using a graphing tool?
Tip: The vertex is always the turning point of the parabola, and its x-coordinate can be found using for any quadratic in standard form.
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Math Problem Analysis
Mathematical Concepts
Algebra
Quadratic Equations
Parabolas
Graphing
Formulas
x = -b / 2a (for vertex)
Quadratic formula: x = (-b ± √(b² - 4ac)) / 2a
f(x) = a(x - h)² + k (vertex form of a quadratic function)
Theorems
Quadratic formula
Vertex of a parabola
Suitable Grade Level
Grades 8-10