Solution - Simplification or other simple results

Reformatting the input :

Changes made to your input should not affect the solution:

 (1): "a2"   was replaced by   "a^2".  1 more similar replacement(s).

Step  1  :

Equation at the end of step  1  :

  (((((a2)+a)+1)+5a2)-8a)+20

Step  2  :

Trying to factor by splitting the middle term

 2.1     Factoring  6a²-7a+21 

The first term is,  6a²  its coefficient is  6 .
The middle term is,  -7a  its coefficient is  -7 .
The last term, "the constant", is  +21 

Step-1 : Multiply the coefficient of the first term by the constant   6 • 21 = 126 

Step-2 : Find two factors of  126  whose sum equals the coefficient of the middle term, which is   -7 .

For tidiness, printing of 18 lines which failed to find two such factors, was suppressed

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

Final result :

  6a2 - 7a + 21