Factored form of the quadratic function

🏆Practice product representation

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=(xt)×(xk)y=(x-t) \times (x-k)

Start practice

Test yourself on product representation!

einstein

Find the standard representation of the following function

\( f(x)=(x-2)(x+5) \)

Practice more now

Where
tt and kk are the intersection points of the parabola with the XX axis.
In the following way: (t,0)(k,0)(t,0) (k,0)
Let's see an example of the factored form:

y=(x7)×(x+2)y=(x-7) \times (x+2)
We can determine that:

the intersection points with the XX axis are:
(7,0) (7,0) 
 (2,0) (- 2,0)
Notice that, since there is a minus sign in the original form before kk and tt, we can deduce that if there is a plus sign before one of them it is negative and, therefore 2-2 and not 22.


Examples and exercises with solutions of the factored form of the quadratic function

Exercise #1

Find the standard representation of the following function

f(x)=(x2)(x+5) f(x)=(x-2)(x+5)

Video Solution

Step-by-Step Solution

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

(a+1)⋆(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) =

x²-2x+5x+-2*5=

x²+3x-10

And that's the solution!

Answer

f(x)+x2+3x10 f(x)+x^2+3x-10

Exercise #2

Find the standard representation of the following function

f(x)=(x6)(x2) f(x)=(x-6)(x-2)

Video Solution

Step-by-Step Solution

To find the standard representation of the quadratic function f(x)=(x6)(x2) f(x) = (x - 6)(x - 2) , follow these steps:

  • Step 1: Apply the FOIL method to expand the expression.
    - First: Multiply the first terms: x×x=x2 x \times x = x^2 .
    - Outside: Multiply the outer terms: x×(2)=2x x \times (-2) = -2x .
    - Inside: Multiply the inner terms: (6)×x=6x (-6) \times x = -6x .
    - Last: Multiply the last terms: (6)×(2)=12 (-6) \times (-2) = 12 .
  • Step 2: Combine the results from the FOIL method.
    - Combine all the expanded terms: x22x6x+12 x^2 - 2x - 6x + 12 .
  • Step 3: Simplify by combining like terms.
    - Combine the x x -terms: 2x6x=8x -2x - 6x = -8x .
    - The expanded and simplified form is: f(x)=x28x+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)=x28x+12 f(x) = x^2 - 8x + 12 .

The correct choice from the provided options is choice 2: f(x)=x28x+12 f(x) = x^2 - 8x + 12 .

Answer

f(x)=x28x+12 f(x)=x^2-8x+12

Exercise #3

Find the standard representation of the following function

f(x)=(x+2)(x4) f(x)=(x+2)(x-4)

Video Solution

Step-by-Step Solution

To find the standard representation of the quadratic function given by f(x)=(x+2)(x4) 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: xx=x2 x \cdot x = x^2 .
  • Outer: Multiply the outer terms in the binomials: x(4)=4x x \cdot (-4) = -4x .
  • Inner: Multiply the inner terms: 2x=2x 2 \cdot x = 2x .
  • Last: Multiply the last terms in each binomial: 2(4)=8 2 \cdot (-4) = -8 .

Now, let's combine these results:

The expression becomes x24x+2x8 x^2 - 4x + 2x - 8 .

Next, we combine like terms:

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

Thus, the expression simplifies to: f(x)=x22x8 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)=x22x8 f(x) = x^2 - 2x - 8 .

Answer

f(x)=x22x8 f(x)=x^2-2x-8

Exercise #4

Find the standard representation of the following function

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

Video Solution

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)=xx+x4=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)=3x2+34x 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

Exercise #5

Find the standard representation of the following function

f(x)=x(x8) f(x)=-x(x-8)

Video Solution

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)=x(x8) f(x) = -x(x - 8) .

Let's go through the necessary steps:

  • Step 1: Apply the distributive property to expand the expression.
    f(x)=x(x8)=xx+(x)(8) f(x) = -x(x - 8) = -x \cdot x + (-x) \cdot (-8)
  • Step 2: Simplify each term.
    xx=x2-x \cdot x = -x^2 and (x)(8)=+8x(-x) \cdot (-8) = +8x.
  • Step 3: Combine the terms to express f(x) f(x) in standard form:
    f(x)=x2+8x f(x) = -x^2 + 8x .

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

Answer

f(x)=x2+8x f(x)=-x^2+8x

Join Over 30,000 Students Excelling in Math!
Endless Practice, Expert Guidance - Elevate Your Math Skills Today
Test your knowledge
Start practice