Here are some strategies you can use to see if an expression is factorable:
- Check for a greatest common factor. If each term has a common factor, it can be moved to the front of the expression. This shows that the polynomial is factorable, and makes it much simpler:
In both terms, there is a coefficient of 7, so it becomes the coefficient of the new expression.
2. Difference of squares. If the expression is a binomial that has subtraction between the two terms, then you know that the factored version has both a negative and positive sign:
3. Check for patterns. If the expression is a trinomial with a pattern of 
