Factor out common factors: Look for common factors in the first two terms and the last two terms separately.We can factor out 5f2 from the first two terms, 5f3 and −5f2.5f3−5f2=5f2(f−1)
Factor out 9: Look for common factors in the last two terms.We can factor out 9 from the last two terms, 9f and −9.9f−9=9(f−1)
Combine factored terms: Now we have factored both pairs of terms:5f3−5f2+9f−9=5f2(f−1)+9(f−1)Notice that (f−1) is a common factor in both terms.
Factor out (f−1): Factor out the common factor (f−1) from both terms.5f2(f−1)+9(f−1)=(f−1)(5f2+9)