tolong bantu ya guyss no 12 buat bsk nihhh plissss???

[tex] u1 = a = \sqrt{3} \\ u2 = 3 + \sqrt{3} \\ b = u2 - u1 = 3 + \sqrt{3} - \sqrt{3} = 3 \\ \\ u3 = a + (n - 1)b \\ u3 = \sqrt{3} + (3 - 1) \times 3 \\ u3 = \sqrt{3} + (2) \times 3 \\ u3 = \sqrt{3} + 6 = 6 + \sqrt{3} [/tex]