191.
Let $$\alpha \,\,{\text{and }}\beta $$ be the roots $${x^2} - 6x - 2 = 0,\,{\text{with }}\alpha > \beta .$$ If $${a_n} = {\alpha ^n} - {\beta ^n}\,\,{\text{for }}n \geqslant 1,$$ then the value of $$\frac{{{a_{10}} - 2{a_8}}}{{2{a_9}}}\,\,{\text{is}}$$
192.
Let $$a, b, c$$ be real numbers and $$a \ne 0.$$ If $$\alpha $$ is a root of $${a^2}{x^2} + bx + c = 0,\beta $$ is a root of $${a^2}{x^2} - bx - c = 0,$$ and $$0 < \alpha < \beta $$ then the equation $${a^2}{x^2} + 2bx + 2c = 0$$ has a root $$\gamma $$ that always satisfies
A
$$\gamma = \frac{1}{2}\left( {\alpha + \beta } \right)$$