Svp aider moi ex 89 et 91 ex facile

(v6+2)(v3-v2)
v6×v3-v6×v2+2v3-2v2
=v18-v12+2v3-2v2
=v9×2 -v4×3 +2v3 -2v2
=3v2-2v3+2v3-2v2
=v2
91/
(2+2v5)^2=2^2+2×2×2v5+(2v5)^2
=4+8v5+20=24+8v5
(3-5v2)=3-30v2+100=103-30v2
(5+2v3)^2=25+20v3+12=37+20v3
(4-3v2)=16-24v2+18=34-24v2