a) x+2 supra x la a2a-4=
x+2 1
------------ = ------- (pt ca x+2~de sus~ si x+2~de jos~ se simplifica)
(x+2)(x-2) x-2
b) (3x-x)² 9x²-6x²+x² 4x² 4x²
--------- = --------------- = ---------- = ---------
(9-x)² (9-x)² (x-9)(9-x) x²-81
c) 4x²-1 (2x-1)(2x+1)
--------- = ----------------- .....nu mai stiu
6x-3 6x-3