A factoring problem that has to be solved by grouping is easy to identify, because you can always identify if there are any similar terms in a polynomial. Now, if you find any variable common in any terms pull them out as the common leaving the rest of the terms. After pulling out the common terms you can group the rest of the polynomial. Be careful while pulling out signs. Pulling out a positive number does not effect the signs of terms in the polynomial, where as pulling out a negative number changes all the signs of terms in the polynomial.