You make a factor tree for (-)40 where the factors of -40 are -8 and +5. This becomes (x+5)(x-8) which can be multiplied to get back to the starting point.
To factorize the given trinomial , you first need to find the factors of -40 such that when multiplied they give -40 and when added they give a result of -3.
The second step in the process of factoring is to write the add the factors up in place of '-3x' to get:
