Лови :3
1) x+2/х+1 + x-2/x-1 - x^2 +1/ х^2 -1= х+2/х+1 - х-2/х-1 - х^2+1/(х-1)(х+1) = (х+2)(х-1)-(х-2)(х+1)-х^2+1/(х-1)(х+1) = х^2-х+2х-2-х^2-х+2х+2-х^2+1/(х-1)(х+1) = -х^2+2х+1/(х-1)(х+1) = -(х+1)^2 /(х-1)(х+1) = -х+1/х-1
2)a^2-a/9-a^2 - a-1/a+3 + a-2/a-3 = a^2-a/(3-a)(3+a) - a-1/a+3 - a-2/3-a = a^2-a-(a-1)(3-a) - (a-2)(3+a)/ (3-a)(3+a) = a^2-a-3a+a^2+3-a-3a-a^2+6+2a/(3-a)(3+a) = a^2-6a+9/(3-a)(3+a) = (a-3)^2/(3-a)(3+a) = -3-a/3+a