Solution - Simplification or other simple results

Reformatting the input :

Changes made to your input should not affect the solution:

 (1): "y3"   was replaced by   "y^3". 

Step  1  :

Trying to factor as a Difference of Cubes:

 1.1      Factoring:  125-y³ 

Theory : A difference of two perfect cubes,  a³ - b³ can be factored into
              (a-b) • (a² +ab +b²)

Proof :  (a-b)•(a²+ab+b²) =
            a³+a²b+ab²-ba²-b²a-b³ =
            a³+(a²b-ba²)+(ab²-b²a)-b³ =
            a³+0+0-b³ =
            a³-b³

Check :  125  is the cube of  5 

Check :  y³ is the cube of   y¹

Factorization is :
             (5 - y)  •  (25 + 5y + y²) 

Trying to factor by splitting the middle term

 1.2     Factoring  y² + 5y + 25 

The first term is,  y²  its coefficient is  1 .
The middle term is,  +5y  its coefficient is  5 .
The last term, "the constant", is  +25 

Step-1 : Multiply the coefficient of the first term by the constant   1 • 25 = 25 

Step-2 : Find two factors of  25  whose sum equals the coefficient of the middle term, which is   5 .

Observation : No two such factors can be found !!
Conclusion : Trinomial can not be factored

Final result :

  (5 - y) • (y2 + 5y + 25)