Factored Form Practice Problems - Quadratic Functions

Master finding x-intercepts and zeros of quadratic functions in factored form. Practice converting between forms with step-by-step solutions and examples.

๐Ÿ“šMaster Factored Form of Quadratic Functions
  • Identify x-intercepts directly from factored form expressions like y=(x-7)(x+2)
  • Convert quadratic functions from standard form to factored form
  • Determine zeros and roots of parabolas using factored representation
  • Solve real-world problems involving quadratic function intersections
  • Apply factored form to find vertex and axis of symmetry
  • Graph quadratic functions using factored form properties

Understanding Product Representation

Complete explanation with examples

Factored form of the quadratic function

This form is called factored because it uses the factors of a multiplication.

With this form, we can easily identify the points of intersection of the function with the XX axis.
The factored form of the quadratic function looks like this:
y=(xโˆ’t)ร—(xโˆ’k)y=(x-t) \times (x-k)

Detailed explanation

Practice Product Representation

Test your knowledge with 29 quizzes

Determine the points of intersection of the function

\( y=(x-3)(x+3) \)

With the X

Examples with solutions for Product Representation

Step-by-step solutions included
Exercise #1

Find the standard representation of the following function

f(x)=(xโˆ’2)(x+5) f(x)=(x-2)(x+5)

Step-by-Step Solution

We will begin by using the distributive property in order to expand the following expression.

(a+1)โ‹†(b+2) = ab+2a+b+2

We will then proceed to insert the known values into the equation and solve as follows:

(x-2)(x+5) =

xยฒ-2x+5x+-2*5=

xยฒ+3x-10

And that's the solution!

Answer:

f(x)+x2+3xโˆ’10 f(x)+x^2+3x-10

Video Solution
Exercise #2

Find the standard representation of the following function

f(x)=(xโˆ’6)(xโˆ’2) f(x)=(x-6)(x-2)

Step-by-Step Solution

To find the standard representation of the quadratic function f(x)=(xโˆ’6)(xโˆ’2) f(x) = (x - 6)(x - 2) , follow these steps:

  • Step 1: Apply the FOIL method to expand the expression.
    - First: Multiply the first terms: xร—x=x2 x \times x = x^2 .
    - Outside: Multiply the outer terms: xร—(โˆ’2)=โˆ’2x x \times (-2) = -2x .
    - Inside: Multiply the inner terms: (โˆ’6)ร—x=โˆ’6x (-6) \times x = -6x .
    - Last: Multiply the last terms: (โˆ’6)ร—(โˆ’2)=12 (-6) \times (-2) = 12 .
  • Step 2: Combine the results from the FOIL method.
    - Combine all the expanded terms: x2โˆ’2xโˆ’6x+12 x^2 - 2x - 6x + 12 .
  • Step 3: Simplify by combining like terms.
    - Combine the x x -terms: โˆ’2xโˆ’6x=โˆ’8x -2x - 6x = -8x .
    - The expanded and simplified form is: f(x)=x2โˆ’8x+12 f(x) = x^2 - 8x + 12 .

By expanding and simplifying the given product, we have converted it to its standard form. Therefore, the standard representation of the function is f(x)=x2โˆ’8x+12 f(x) = x^2 - 8x + 12 .

The correct choice from the provided options is choice 2: f(x)=x2โˆ’8x+12 f(x) = x^2 - 8x + 12 .

Answer:

f(x)=x2โˆ’8x+12 f(x)=x^2-8x+12

Video Solution
Exercise #3

Find the standard representation of the following function

f(x)=(x+2)(xโˆ’4) f(x)=(x+2)(x-4)

Step-by-Step Solution

To find the standard representation of the quadratic function given by f(x)=(x+2)(xโˆ’4) f(x) = (x+2)(x-4) , we will expand the expression using the distributive property, commonly known as the FOIL method (First, Outer, Inner, Last):

  • First: Multiply the first terms in each binomial: xโ‹…x=x2 x \cdot x = x^2 .
  • Outer: Multiply the outer terms in the binomials: xโ‹…(โˆ’4)=โˆ’4x x \cdot (-4) = -4x .
  • Inner: Multiply the inner terms: 2โ‹…x=2x 2 \cdot x = 2x .
  • Last: Multiply the last terms in each binomial: 2โ‹…(โˆ’4)=โˆ’8 2 \cdot (-4) = -8 .

Now, let's combine these results:

The expression becomes x2โˆ’4x+2xโˆ’8 x^2 - 4x + 2x - 8 .

Next, we combine like terms:

The terms involving x x are โˆ’4x+2x -4x + 2x , which simplifies to โˆ’2x -2x .

Thus, the expression simplifies to: f(x)=x2โˆ’2xโˆ’8 f(x) = x^2 - 2x - 8

Upon comparing this result to the provided choices, we find that it matches choice 3.

Therefore, the standard representation of the function is f(x)=x2โˆ’2xโˆ’8 f(x) = x^2 - 2x - 8 .

Answer:

f(x)=x2โˆ’2xโˆ’8 f(x)=x^2-2x-8

Video Solution
Exercise #4

Find the standard representation of the following function

f(x)=3x(x+4) f(x)=3x(x+4)

Step-by-Step Solution

To find the standard representation of the quadratic function f(x)=3x(x+4) f(x) = 3x(x + 4) , follow these steps:

  • Step 1: Apply the distributive property to expand the expression x(x+4) x(x + 4) .
    Using this property, we have:
    x(x+4)=xโ‹…x+xโ‹…4=x2+4x x(x + 4) = x \cdot x + x \cdot 4 = x^2 + 4x .
  • Step 2: Multiply each term by the coefficient outside the parenthesis, which is 3.
    This gives us:
    3(x2+4x)=3โ‹…x2+3โ‹…4x 3(x^2 + 4x) = 3 \cdot x^2 + 3 \cdot 4x .
  • Step 3: Simplify by performing the multiplication.
    3x2+12x 3x^2 + 12x .

Therefore, the standard representation of the function is f(x)=3x2+12x f(x) = 3x^2 + 12x . This matches choice 3 in the provided answers.

Answer:

f(x)=3x2+12x f(x)=3x^2+12x

Video Solution
Exercise #5

Find the standard representation of the following function

f(x)=โˆ’x(xโˆ’8) f(x)=-x(x-8)

Step-by-Step Solution

To solve this problem, we'll convert the given function from its factored form to the standard form using the distributive property. The given function is f(x)=โˆ’x(xโˆ’8) f(x) = -x(x - 8) .

Let's go through the necessary steps:

  • Step 1: Apply the distributive property to expand the expression.
    f(x)=โˆ’x(xโˆ’8)=โˆ’xโ‹…x+(โˆ’x)โ‹…(โˆ’8) f(x) = -x(x - 8) = -x \cdot x + (-x) \cdot (-8)
  • Step 2: Simplify each term.
    โˆ’xโ‹…x=โˆ’x2-x \cdot x = -x^2 and (โˆ’x)โ‹…(โˆ’8)=+8x(-x) \cdot (-8) = +8x.
  • Step 3: Combine the terms to express f(x) f(x) in standard form:
    f(x)=โˆ’x2+8x f(x) = -x^2 + 8x .

Therefore, the standard representation of the function is f(x)=โˆ’x2+8x f(x) = -x^2 + 8x .

Comparing this result to the multiple-choice options, we can see that the correct choice is option 3: f(x)=โˆ’x2+8x f(x)=-x^2+8x .

Answer:

f(x)=โˆ’x2+8x f(x)=-x^2+8x

Video Solution

Frequently Asked Questions

What is the factored form of a quadratic function?

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The factored form of a quadratic function is y=(x-t)(x-k), where t and k are the x-intercepts of the parabola. This form makes it easy to identify where the function crosses the x-axis at points (t,0) and (k,0).

How do you find x-intercepts from factored form?

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To find x-intercepts from factored form y=(x-t)(x-k), set y=0 and solve: (x-t)(x-k)=0. This gives x=t and x=k as the x-intercepts. Remember to watch the signs: if you see (x+2), the x-intercept is -2, not +2.

Why does y=(x-7)(x+2) have x-intercepts at 7 and -2?

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When y=0, we get (x-7)(x+2)=0. For this product to equal zero, either x-7=0 (so x=7) or x+2=0 (so x=-2). The minus sign before each variable in the factored form determines the actual intercept values.

What's the difference between factored form and standard form?

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Standard form is y=axยฒ+bx+c, while factored form is y=(x-t)(x-k). Factored form immediately shows x-intercepts, while standard form shows the y-intercept. You can expand factored form to get standard form, or factor standard form to get factored form.

How do you convert from standard form to factored form?

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To convert axยฒ+bx+c to factored form: 1) Factor out 'a' if needed, 2) Find two numbers that multiply to give ac and add to give b, 3) Use these to write the factored form. For example, xยฒ-5x+6 becomes (x-2)(x-3).

Can all quadratic functions be written in factored form?

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Not all quadratic functions can be factored using real numbers. If the discriminant (bยฒ-4ac) is negative, the quadratic has no real x-intercepts and cannot be factored over the real numbers. It would require complex numbers.

What if a quadratic function has only one x-intercept?

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When a quadratic has only one x-intercept, it's called a perfect square trinomial. The factored form looks like y=(x-h)ยฒ, where h is the single x-intercept. For example, y=xยฒ-6x+9 factors to y=(x-3)ยฒ.

How does factored form help with graphing parabolas?

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Factored form y=(x-t)(x-k) immediately gives you the x-intercepts at (t,0) and (k,0). The vertex x-coordinate is the midpoint: x=(t+k)/2. You can then find the y-coordinate of the vertex and determine if the parabola opens up or down.

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