Answer:
[tex]x^2-210=0\quad\implies\quad a=1\,,\ b=0\,,\ c=-210\\\\b^2-4ac=0-(-810)=810>0[/tex]
From Vieta's formulas applied to quadratic polynomial we have:
if [tex]b^2-4ac\geqslant0[/tex] then
sum of roots: [tex]x_1+x_2=-\dfrac ba=-\dfrac{0}2=0[/tex]
product of the roots: [tex]x_1x_2=\dfrac ca=\dfrac{-210}1=-210[/tex]