How do you figure out what is a trinomial?

To factor trinomals in the form of x^2+bx+c, you have to find 2 integers, r and s, whose product is c, and whose sum is b. You have to rewrite the trinomial as x^2+rx+sx+c and then using the grouping and distribution of property to factor the polynomial. The result of the factors will be (x+r) and (x+s)