Question

Запарился с теоремой Виета

Answer 1

$\frac{1}{ x_{1} ^{2} }+ \frac{1}{ x_{2} ^{2} }= \frac{ x_{1} ^{2} + x_{2} ^{2} }{( x_{1}* x_{2} ) ^{2} } = \frac{( x_{1}+ x_{2}) ^{2}-2 x_{1}* x_{2} }{( x_{1} * x_2) ^{2} } }= \frac{2,5 ^{2}-2*(-2) }{(-2) ^{2} }= \frac{6,25+4}{4} =2,5625$