Помогите пожалуйста 216(1,2)

216.1) (a-1)(a²+a+1) - a²(a-8) = a³ + a² + a - a² - a - 1 - a³ + 8a² = 9a² - 1 = (3a-1)(3a+1) a = [latex] \frac{2}{9} [/latex]  [latex] \frac{3*2}{9} - 1 = \frac{2}{3} - 1 = - \frac{1}{3} [/latex] [latex] \frac{3*2}{9} + 1 = \frac{2}{3} + 1 = 1 \frac{2}{3} [/latex] [latex]- \frac{1*5}{3*3} = - \frac{5}{9} [/latex] 216.2) (b+2)(b² - 2b + 4) - b(b²-1) = b³ - 2b² + 4b + 2b² - 4b + 8 - b³ + b = b+8 [latex]- \frac{2}{3} + 8 = 7 \frac{1}{3} [/latex] Удачи!