Question

Помогите плиз, даю 30 балов

Answer 1

2x^2-5x-1=0;

D=25-4×2×(-1)=25+8=33

x1=(5-sqrt33)/4

x2=(5+sqrt33)/4

Проверим:

По теорема Виета

x1+x2=-(b/a)=5/2

x1+x2=(5-sqrt33)/4+(5+sqrt33)/4=5/4+5/4=5/2

x1×x2=c/a=-1/2

x1×x2=(5-sqrt33)/4×(5+sqrt33)/4=

=(25-33)/16=-8/16=-1/2