Solution - Simplification or other simple results

Step  1  :

Equation at the end of step  1  :

  (22x2 -  21x) -  18

Step  2  :

Trying to factor by splitting the middle term

 2.1     Factoring  4x²-21x-18 

The first term is,  4x²  its coefficient is  4 .
The middle term is,  -21x  its coefficient is  -21 .
The last term, "the constant", is  -18 

Step-1 : Multiply the coefficient of the first term by the constant   4 • -18 = -72 

Step-2 : Find two factors of  -72  whose sum equals the coefficient of the middle term, which is   -21 .

Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above,  -24  and  3 
                     4x² - 24x + 3x - 18

Step-4 : Add up the first 2 terms, pulling out like factors :
                    4x • (x-6)
              Add up the last 2 terms, pulling out common factors :
                    3 • (x-6)
Step-5 : Add up the four terms of step 4 :
                    (4x+3)  •  (x-6)
             Which is the desired factorization

Final result :

  (x - 6) • (4x + 3)