Solution - Simplification or other simple results

Step  1  :

Equation at the end of step  1  :

  (3x2 +  20x) -  7

Step  2  :

Trying to factor by splitting the middle term

 2.1     Factoring  3x²+20x-7 

The first term is,  3x²  its coefficient is  3 .
The middle term is,  +20x  its coefficient is  20 .
The last term, "the constant", is  -7 

Step-1 : Multiply the coefficient of the first term by the constant   3 • -7 = -21 

Step-2 : Find two factors of  -21  whose sum equals the coefficient of the middle term, which is   20 .

Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above,  -1  and  21 
                     3x² - 1x + 21x - 7

Step-4 : Add up the first 2 terms, pulling out like factors :
                    x • (3x-1)
              Add up the last 2 terms, pulling out common factors :
                    7 • (3x-1)
Step-5 : Add up the four terms of step 4 :
                    (x+7)  •  (3x-1)
             Which is the desired factorization

Final result :

  (3x - 1) • (x + 7)