Respuesta :

Answer:

For Answer 7 its the first one   (x + 6) • (x - 7)

Step-by-step explanation:

Step  1  :

Trying to factor by splitting the middle term

1.1     Factoring  x2-x-42  

The first term is,  x2  its coefficient is  1 .

The middle term is,  -x  its coefficient is  -1 .

The last term, "the constant", is  -42  

Step-1 : Multiply the coefficient of the first term by the constant   1 • -42 = -42  

Step-2 : Find two factors of  -42  whose sum equals the coefficient of the middle term, which is   -1 .

     -42    +    1    =    -41  

     -21    +    2    =    -19  

     -14    +    3    =    -11  

     -7    +    6    =    -1    That's it

Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above,  -7  and  6  

                    x2 - 7x + 6x - 42

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

                   x • (x-7)

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

                   6 • (x-7)

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

                   (x+6)  •  (x-7)

            Which is the desired factorization

Final result :

 (x + 6) • (x - 7)