Solve for x 2) 21x-4=20x

Step-by-step explanation:

(−4x−1)⋅(5x+4)

Step-1 : Multiply the coefficient of the first term by the constant   20 • 4 = 80

Step-2 : Find two factors of  80  whose sum equals the coefficient of the middle term, which is   21 .

     -80    +    -1    =    -81

     -40    +    -2    =    -42

     -20    +    -4    =    -24

     -16    +    -5    =    -21

     -10    +    -8    =    -18

     -8    +    -10    =    -18

     -5    +    -16    =    -21

     -4    +    -20    =    -24

     -2    +    -40    =    -42

     -1    +    -80    =    -81

     1    +    80    =    81

     2    +    40    =    42

     4    +    20    =    24

     5    +    16    =    21    That's it

Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above,  5  and  16

                    20x2 + 5x + 16x + 4

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

                   5x • (4x+1)

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

                   4 • (4x+1)

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

                   (5x+4)  •  (4x+1)

            Which is the desired factorization=(−4x−1)⋅(5x+4)

first one

step-by-step explanation:

sorry, i can't understand your question. will later if you describe more clearly!

: )