1) t^2-8/4=0
t^2-2=0
t^2=2
t1=2
t2=-2
2) (x+1)/(x-2)-x/(x+2)=12/(x^2-4)
((x+1)(x+2)-x(x-2))/((x-2)(x+2))=12/(x^2-4)
(5x+2)/(x^2-4)=12/(x^2-4)
((5x+2)/(x^2-4))-12/(x^2-4)=0
(5x+2-12)/(x^2-4)=0
5x-10=0
5x=10
x=10/5=2
^(степень)
/(деление)
(x-2)(x+2)=x^2+2x-2x-4=x^2-4