Need help with thisss

The first term is,  x2  its coefficient is  1 .

The middle term is,  +5x  its coefficient is  5 .

The last term, "the constant", is  +21 

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

Step-2 : Find two factors of  21  whose sum equals the coefficient of the middle term, which is   5 .

     -21   +   -1   =   -22     -7   +   -3   =   -10     -3   +   -7   =   -10     -1   +   -21   =   -22     1   +   21   =   22     3   +   7   =   10     7   +   3   =   10     21   +   1   =   22