The middle term is to be splitted in such a way that the product of two numbers gives the c term in the equation and there sum gives the middle we can replace middle term by these 2 numbers.
for example 
if 10 is the middle term and 7 is the c term
then 10 can be written as the product of 2*5 and the sum of the numbers gives the third term 7
1 4 1
thank you soooo much!!! :)
mark best