6.
a)√48+√15*(2/√3-4/√5)+(√5-1)²=
4√3+10√45/15-12√75/15+5-2√5+1=
4√3+2√5-4√3+5-2√5+1=6
b)[(√2-√3)²+√24]*(√50)^-1
[√2²-2√6+√3²+2√6]*(√50)^-1=
5*1/√50=
5*1/5√2=√2/2
c)√21+12√3+|3-2√3|-(√3+2)²
2√3+3-3+2√3-3-4√3-4=-7
7. |x-3/2|<=3
x-3/2<=3
x<=9
-x+3/2<=3
-x+3<=6
-x<=3
x>=-3
-3<=x<=9
x∈{-3,-2,-1,1,2,3,4,5,6,7,8,9}
A={-3,-2,-1,1,2,3,4,5,6,7,8,9}
3x+8/2x-3∈Z
2x-3 | 2x-3 (1)
2x-3 | 3x+8 (2)
(1) inmultim relatia cu 3
(2) inmultin relatia cu 2
2x-3| 7
2x-3 trebuie sa apartina divizorilor lui 7
D7={-1,1,7,-7}
2x-3=1
2x=4
x=2
2x-3=-1
2x=-2
x=1
2x-3=7
x=5
2x-3=-7
x=-2
B={1,2,5,-2}
A∩B={1,2,5,-2}
