in order to factor this you have to divide in 2 the first and last to get the middle term, now 2 can only be divided in 2 by multiplying 2 by 1 so those are your first terms now for 15 it can be divided by 2 if you multiply 3 times 5 now we have (2x+3)(x+5) since the polynomial has 2 positives both signs will be positive so that would be your answer
Hope this helps