Question

Factorise X cube-2x square-29x-42

Answer 1

hey mate your answer

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

Step-2 : Find two factors of  6  whose sum equals the coefficient of the middle term, which is   5 .

     -6    +    -1    =    -7  

     -3    +    -2    =    -5  

     -2    +    -3    =    -5  

     -1    +    -6    =    -7  

     1    +    6    =    7  

     2    +    3    =    5    That's it

Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above,  2  and  3  

                    x2 + 2x + 3x + 6

Step-4 : Add up the first 2 terms, pulling out like factors :

                   x • (x+2)

             Add up the last 2 terms, pulling out common factors :

                   3 • (x+2)

Step-5 : Add up the four terms of step 4 :

                   (x+3)  •  (x+2)

            Which is the desired factorization