Respuesta :

Solving step by step:

2y + 2 = 36

Move the constant to the right and change the sign.

2y = 36 - 2

Calculate the right side.

2y = 34

Divide both sides by 2.

y = 17

Answer:

y = 3 • ± √2 = ± 4.2426

Step-by-step explanation:

2y2 -  36  = 0  

Step  2  :

Step  3  :

Pulling out like terms :

3.1     Pull out like factors :

  2y2 - 36  =   2 • (y2 - 18)  

Trying to factor as a Difference of Squares :

3.2      Factoring:  y2 - 18  

Theory : A difference of two perfect squares,  A2 - B2  can be factored into  (A+B) • (A-B)

Proof :  (A+B) • (A-B) =

        A2 - AB + BA - B2 =

        A2 - AB + AB - B2 =  

        A2 - B2

Note :  AB = BA is the commutative property of multiplication.  

Note :  - AB + AB equals zero and is therefore eliminated from the expression.

Check : 18 is not a square !!  

Ruling : Binomial can not be factored as the difference of two perfect squares.

Equation at the end of step  3  :

 2 • (y2 - 18)  = 0  

Step  4  :

Equations which are never true :

4.1      Solve :    2   =  0

This equation has no solution.

A a non-zero constant never equals zero.

Solving a Single Variable Equation :

4.2      Solve  :    y2-18 = 0  

Add  18  to both sides of the equation :  

                     y2 = 18  

 

When two things are equal, their square roots are equal. Taking the square root of the two sides of the equation we get:  

                     y  =  ± √ 18  

Can  √ 18 be simplified ?

Yes!   The prime factorization of  18   is

  2•3•3  

To be able to remove something from under the radical, there have to be  2  instances of it (because we are taking a square i.e. second root).

√ 18   =  √ 2•3•3   =

               ±  3 • √ 2  

The equation has two real solutions  

These solutions are  y = 3 • ± √2 = ± 4.2426

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