Question 1145990
3x^2+16x+5

The first term is,  3x^2  its coefficient is  3 .
The middle term is,  +16x  its coefficient is  -16 .
The last term, "the constant", is  +5 

Step-1 : Multiply the coefficient of the first term by the constant   3 * 5 = 15 

Step-2 : Find two factors of  15  whose sum equals the coefficient of the middle term, which is   +16 .

     	15	   +   	1	   =   	16	   

Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above,  15  and  1 
                     3x^2 + 15x + 1x +5

Step-4 : Add up the first two terms, pulling out like factors :
                    3x * (x+5)
              Add up the last two terms, pulling out common factors :
                     1 * (x+5)
Step-5 : Add up the four terms of step 4 :
                    (3x+1)*(x+5)