susunlah persamaan kuadrat jika diketahui akar akarnya 1 dan -9

(x - a)(x - b) = 0
(x - 1)(x - (-9)) = 0
(x - 1)(x + 9) = 0
x² + 9x - x - 9 = 0
x² + 8x - 9 = 0