We have to complete the given statement.
Whenever we factorize a trinomial, our first step is to figure out the common factor in each term and then we factor it out.
For example: Consider any trinomial say

So, our first step is look for the common factor in each term.
We can observe that '5' is common factor in each of the term. So, taking '5' as common from each of the term, we get as
=

So, "In factoring a trinomial with a leading coefficient other than 1, the first step is to look for a common factor in each term and factor it out".