What is the factorization of the trinomial below. -x2 - 2x plus 48?

First, I'll multiply by -1, to make it a little easier to work with (then when done, I'll multiply by -1 again): x2 + 2x - 48. We want two numbers, when multiplied yield -48, and the sum is 2: -6 and 8. (x + 8)(x - 6) works. Now multiply one of the binomial factors by -1: (x + 8)(6 - x). Multiply using FOIL to check: -x2 - 2x + 48