Question

Алгебрааааааа проооошууу пж помогииитеее,на русском найдите а) и в)
х^2-7х-9=0​

Answer 1

$x^{2}-7x-9=0\\\\\boxed{x_{1} +x_{2}=7}\\\\\boxed{x_{1}*x_{2}=-9}-teorema \ Vieta\\\\\frac{1}{x_{1}}+\frac{1}{x_{2}}=\frac{x_{1}+x_{2}}{x_{1}*x_{2}}=\frac{7}{-9}=\boxed{-\frac{7}{9}}$