It is very important that you and avoid errors to happen.
Review
Instruction:
Factor each of the following quadratic expression.
1. x² + x
2. 5x2 - 25x
3. x2 - 16
4. x² + 4x + 4
5. x2 - 5x + 6

Step-by-step explanation:

Given expressions:

1. x² + x

2. 5x² - 25x

3. x² - 16

4. x² + 4x + 4

5. x² - 5x + 6

   Problem: Factor each of the quadratic expression

Solution:

A quadratic expression is an expression whose highest power is two.

1. x² + x

     For this expression:

       x² + x

    Factorizing x since  it is a common term;

       x(x + 1)          

2. 5x² - 25x

    For this expression;

   Factorize 5x since it common to both of them;

      5x(x - 5)

3. x² - 16

    For this expression;

  Apply the differences of two squares;

     x² - 16

     x² - 4²;

    Note;  x² - y²  = (x-y)(x+y)

So, x² - 4² = (x-4)(x + 4)

4. x² + 4x + 4

   To solve this,

     Find two numbers whose product will be 4 and sum also 4;

  x² + 4x + 4 = x² + 2x + 2x + 4

                    = x(x + 2) + 2(x + 2)

                     = (x + 2)(x + 2)

5. x² - 5x + 6

    To factorize this expression, simply find two numbers whose sum is -5 and product is 6;

            x² - 5x + 6 = x² - 3x - 2x + 6

                              = x (x - 3) -2(x - 3)  

                              = (x -2)(x-3)

table 3 represents a direct variation function. : )