Question

СРОЧНО! ПОМОГИТЕ.

127(1,3)
129(1)​

Answer 1

127)

$x^{2}-3x-4=0\\\\x_{1}+x_{2}=3\\\\x_{1}*x_{2}=-4\\\\\frac{1}{x_{1}}+\frac{1}{x_{2}}=\frac{x_{1}+x_{2}}{x_{1}*x_{2}}=\frac{3}{-4}=-0,75\\\\Otvet:\boxed{-0,75}\\\\x_{1}^{3}+x_{2}^{3}=(x_{1}+x_{2})(x_{1}^{2}-x_{1}*x_{2}+x_{2}^{2})=(x_{1}+x_{2} )((x_{1}+x_{2})^{2}-3x_{1}x_{2})=3*(3^{2} -3*(-4))=3*(9+12)=3*21=63\\\\Otvet:\boxed{63}$

$129)\\\\x*\sqrt{x-1} =0\\\\\left[\begin{array}{ccc}x=0\\\sqrt{x-1}=0 \end{array}\right\\\\\left[\begin{array}{ccc}x=0\\x-1=0\end{array}\right\\\\\left[\begin{array}{ccc}x_{1}=0 \\x_{2}=1 \end{array}\right\\\\Otvet:\boxed{0;1}$