Question 451671
This can be written as


{{{x^2-1-8=0}}}
{{{x^2-9=0}}}, this is now difference of two squared numbers, x and 3
{{{x^2-3^2=0}}}, this is product of sum and differnce x and 3
{{{(x+3)(x-3)=0}}}


So it can be


{{{x+3=0}}} -> x=-3
{{{x-3=0}}} -> x= 3


We say roots of this quadratic equation are 3 and -3.