Show that (x+1)(x+3)(x+5) can be written in the form ax^3+bx^2+cx+d where a, b and c are all positive integers, and d is a negative integer

The probability that a student graduating from suburban state university has student loans to pay off after graduation is .60. if two students are randomly selected from this university, what is the probability that neither of them has student loans to pay off after graduation?