Помогите решить 34.23

Воспользуемся теоремой Виета.
$x_{1} ^{2} x_{2}+x_{1}x_{2}^{2}=(x_{1}+x_{2})(x_{1}x_{2})=(-5)(-16)=80$
$x_{2}/x_{1}+x_{1}/x_{2}=(x_{2}^2+x_{1}^2)/(x_{1}x_{2})=((x_{1}+x_{2})^2-2x_{1}x_{2})/(x_{1}x_{2})$
((-5)^2+2*16)/(-16)=-(25+32)/16=-57/16

x_{1}=(-b-sqrt(D))/(2a)
x_{2}=(-b+sqrt(D))/(2a)
x_{2}-x_{1}=sqrt(D)/a
abs(x_{2}-x_{1})=abc(sqrt(D)/a)
D=25+4*16=25+64=89
abs(x_{2}-x{1})=89