Since we see u² as the first term, we know that the factored form will be something like: (u ± something)(u ± something)
We also know that the sum of these 'somethings' is 1, and he product is negative 30 (because that's 1 u, and -30). The two numbers that have a sum of 1 and a product of -30 are 6 and -5, so the factored form of this trinomial is (u + 6)(u - 5)