-- Look at both terms.
Notice that they can both be divided by 3.
Factor out 3 .
3 (3a³ + 5a²)
-- Look at the terms inside the parentheses.
Notice that they can both be divided by a² .
Factor the a² out, to the outside of the parentheses.
3 a² (3a + 5)
No factor left that's common to both terms
inside the parentheses.
So it's now completely factored.
