Quadratic Function Practice Problems - Parabola Vertex & Graph

Master quadratic functions with step-by-step practice problems. Learn to find parabola vertex, identify maximum/minimum, and determine domains of increase.

📚Master Quadratic Functions Through Interactive Practice
  • Find parabola vertex using formula X = -b/2a and symmetric points method
  • Identify maximum and minimum parabolas by analyzing coefficient 'a'
  • Calculate intersection points with X and Y axes using algebraic methods
  • Determine domains of increase and decrease for quadratic functions
  • Find positive and negative domains by analyzing parabola position
  • Solve real-world problems involving quadratic function applications

Understanding The Quadratic Function

Complete explanation with examples

The Parabola y=ax2+bx+c y=ax^2+bx+c 

This function is a quadratic function and is called a parabola.

We will focus on two main types of parabolas: maximum and minimum parabolas.

Minimum Parabola

Also called smiling or happy.

A vertex is the minimum point of the function, where YY is the lowest.

We can identify that it is a minimum parabola if the aa equation is positive.

1b - We can identify that it is a minimum parabola if the equation a is positive


Maximum Parabola

Also called sad or crying.

A vertex is the maximum point of the function, where YY is the highest.

We can identify that it is a maximum parabola if the aa equation is negative.

2b - We can identify that it is a maximum parabola if the a equation is negative

To the parabola,

the vertex marks its highest point.

How do we find it?


Detailed explanation

Practice The Quadratic Function

Test your knowledge with 17 quizzes

\( y=x^2 \)

Examples with solutions for The Quadratic Function

Step-by-step solutions included
Exercise #1

Determine the value of the coefficient a a in the following equation:

x2+7x9 -x^2+7x-9

Step-by-Step Solution

The quadratic equation in the problem is already arranged (meaning all terms are on one side and 0 on the other side), so let's proceed to answer the question asked:

The question asked in the problem - What is the value of the coefficienta a in the equation?

Let's recall the definitions of coefficients in solving quadratic equations and the roots formula:

The rule states that the roots of an equation of the form:

ax2+bx+c=0 ax^2+bx+c=0 are:

x1,2=b±b24ac2a x_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

That is the coefficient a a is the coefficient of the quadratic term (meaning the term with the second power)- x2 x^2 Let's examine the equation in the problem:

x2+7x9=0 -x^2+7x-9 =0

Remember that the minus sign before the quadratic term means multiplication by: 1 -1 , therefore- we can write the equation as:

1x2+7x9=0 -1\cdot x^2+7x-9 =0

The number that multiplies the x2 x^2 , is 1 -1 hence we identify that the coefficient of the quadratic term is the number 1 -1 ,

Therefore the correct answer is A.

Answer:

-1

Video Solution
Exercise #2

What is the value of the coefficient b b in the equation below?

3x2+8x5 3x^2+8x-5

Step-by-Step Solution

The quadratic equation of the given problem is already arranged (that is, all the terms are found on one side and the 0 on the other side), thus we approach the given problem as follows;

In the problem, the question was asked: what is the value of the coefficientb b in the equation?

Let's remember the definitions of coefficients when solving a quadratic equation as well as the formula for the roots:

The rule says that the roots of an equation of the form

ax2+bx+c=0 ax^2+bx+c=0 are :

x1,2=b±b24ac2a x_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

That is the coefficientb b is the coefficient of the term in the first power -x x We then examine the equation of the given problem:

3x2+8x5=0 3x^2+8x-5 =0 That is, the number that multiplies

x x is

8 8 Consequently we are able to identify b, which is the coefficient of the term in the first power, as the number8 8 ,

Thus the correct answer is option d.

Answer:

8

Video Solution
Exercise #3

What is the value of the coefficient c c in the equation below?

4x2+9x2 4x^2+9x-2

Step-by-Step Solution

The quadratic equation is given as 4x2+9x2 4x^2 + 9x - 2 . This equation is in the standard form of a quadratic equation, which is ax2+bx+c ax^2 + bx + c , where a a , b b , and c c are coefficients.

  • The term 4x2 4x^2 indicates that the coefficient a=4 a = 4 .
  • The term 9x 9x indicates that the coefficient b=9 b = 9 .
  • The constant term 2-2 indicates that the coefficient c=2 c = -2 .

From this analysis, we can see that the coefficient c c is 2-2.

Therefore, the value of the coefficient c c in the equation is 2-2.

Answer:

-2

Video Solution
Exercise #4

What is the value of the coefficient c c in the equation below?

3x2+5x 3x^2+5x

Step-by-Step Solution

The quadratic equation of the given problem has already been arranged (that is, all the terms are on one side and 0 is on the other side) thus we can approach the question as follows:

In the problem, the question was asked: what is the value of the coefficientc c in the equation?

Let's remember the definition of a coefficient when solving a quadratic equation as well as the formula for the roots:

The rule says that the roots of an equation of the form

ax2+bx+c=0 ax^2+bx+c=0 are:

x1,2=b±b24ac2a x_{1,2}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

That is the coefficient
c c is the free term - and as such the coefficient of the term is raised to the power of zero -x0 x^0 (Any number other than zero raised to the power of zero equals 1:

x0=1 x^0=1 )

Next we examine the equation of the given problem:

3x2+5x=0 3x^2+5x=0 Note that there is no free term in the equation, that is, the numerical value of the free term is 0, in fact the equation can be written as follows:

3x2+5x+0=0 3x^2+5x+0=0 and therefore the value of the coefficientc c is 0.

Hence the correct answer is option c.

Answer:

0

Video Solution
Exercise #5

y=x2+x+5 y=x^2+x+5

Step-by-Step Solution

To solve this problem, we will identify the parameters of the given quadratic function step-by-step:

  • Step 1: Define the problem statement: We have y=x2+x+5 y = x^2 + x + 5 .
  • Step 2: Identify the standard form of a quadratic function, which is y=ax2+bx+c y = ax^2 + bx + c .
  • Step 3: Compare the given quadratic expression with the standard form to identify the coefficients.

Now, let's analyze the quadratic function provided:

From the given expression y=x2+x+5 y = x^2 + x + 5 :
- The coefficient of x2 x^2 is 1 1 , so a=1 a = 1 .
- The coefficient of x x is 1 1 , so b=1 b = 1 .
- The constant term is 5 5 , so c=5 c = 5 .

Therefore, the parameters of the quadratic function are a=1 a = 1 , b=1 b = 1 , and c=5 c = 5 .

Consequently, the correct choice from the provided options is (a=1,b=1,c=5) (a = 1, b = 1, c = 5) .

Answer:

a=1,b=1,c=5 a=1,b=1,c=5

Video Solution

Frequently Asked Questions

How do you find the vertex of a parabola y = ax² + bx + c?

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Use the vertex formula X = -b/2a to find the x-coordinate. Then substitute this value back into the original equation to find the y-coordinate. Alternatively, you can use two symmetric points and find their midpoint.

What determines if a parabola opens upward or downward?

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The coefficient 'a' in y = ax² + bx + c determines the direction. If a > 0, the parabola opens upward (minimum/smiling). If a < 0, the parabola opens downward (maximum/sad).

How many x-intercepts can a quadratic function have?

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A parabola can have 0, 1, or 2 x-intercepts. To find them, set y = 0 and solve the quadratic equation using factoring, completing the square, or the quadratic formula.

What is the difference between domains of increase and decrease?

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Domain of increase: x-values where the parabola rises (y increases as x increases). Domain of decrease: x-values where the parabola falls (y decreases as x increases). The vertex marks where this behavior changes.

How do you find positive and negative domains of a parabola?

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1. Find x-intercepts by setting y = 0 2. Plot the parabola 3. Positive domain: x-values where graph is above x-axis (y > 0) 4. Negative domain: x-values where graph is below x-axis (y < 0)

What is the y-intercept of a quadratic function?

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The y-intercept is found by setting x = 0 in the equation y = ax² + bx + c. This gives y = c, so the y-intercept is always the constant term 'c'.

Why is the vertex important in quadratic functions?

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The vertex represents the maximum or minimum point of the parabola. It's where the function changes from increasing to decreasing (or vice versa) and is crucial for understanding the function's behavior and solving optimization problems.

How do you determine if a quadratic function has real solutions?

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Calculate the discriminant b² - 4ac. If positive: 2 real solutions (2 x-intercepts). If zero: 1 real solution (1 x-intercept). If negative: no real solutions (no x-intercepts).

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