Solution - Linear equations with one unknown

Step by step solution :

Step  1  :

Step  2  :

Pulling out like terms :

 2.1     Pull out like factors :

   d² - 2d  =   d • (d - 2) 

Equation at the end of step  2  :

  d • (d - 2)  = 0 

Step  3  :

Theory - Roots of a product :

 3.1    A product of several terms equals zero. 

 When a product of two or more terms equals zero, then at least one of the terms must be zero. 

 We shall now solve each term = 0 separately 

 In other words, we are going to solve as many equations as there are terms in the product 

 Any solution of term = 0 solves product = 0 as well.

Solving a Single Variable Equation :

 3.2      Solve  :    d = 0 

  Solution is  d = 0

Solving a Single Variable Equation :

 3.3      Solve  :    d-2 = 0 

 Add  2  to both sides of the equation : 
                      d = 2

Two solutions were found :

1.  d = 2
2.  d = 0