1) √3 -3 +1 -√3 +6= -3 +1 +6= -3+7=4
2)a) mas<FAB= mas<FOA+mas<BAO=60+60=120 grade
hexagonul regulat este compus din 6 triunghiuri echilaterale
b)A FABO= A ΔFAO + A ΔBAO= 2*A ΔFAO
A ΔFAO= l²√3/4= (6√3)² *√3/4= 108√3/4= 27√3
A FABO= 2*27√3= 54√3
c) FABO-patrulater convex
AF=AB=OB=OF =6√3 =>FABO -patrat
<=> FB=l√2= 6√3 *√2= 6√6
FEDO-patrulater convex
FE=ED=FO=OD =>FEDO-patrat
<=>FD= l√2= 6√3* √2=6√6
BOCD-patrulater convex
OB=OD=DC=BC =>BOCD-patrat
<=> BD= l√2= 6√3 * √2= 6√6
P ΔFBD= FD+BD+FB= 6√6+6√6+6√6= 18√6
Δ FBD-echilateral, FD=BD=FB=6√6
3)x+y=5
x²-y²= 45
(x-y)(x+y)=45
5(x-y)=45
(x-y)=9
5y-5x = 5(y-x)= -5(x-y) = -5 *9 = -45
4)F(√2) = [1- 2* (√2)² ] /(√2)² +1=
= ( 1 -2*2) /(2+1)=
= (1-4)/3=
= -3/3 = -1
