We have the common factor (x+3) show up for each of the two terms. The first term is 2x(x+3) while the second term is 5(x+3).
For each of the two terms, erase the common factor (x+3) and you'll be left with 2x+5, which is one of the factors in the final answer. The second factor is the common factor (x+3). Together they combine to get us (2x+5)(x+3)
