14
a) A={1,3}
b) x= 2ⁿ ,n≤5
n= 0,1,2,3,4,5
x= 1,2,4,8,16,32
B={1,2,4,8,16,32}
c)
x² < 12
x² ≥ 9
x²= 3²=9
C={3}
d) n² este un patrat perfect
patratele perfecte se termina in cifrele: 4,6,5,9,1,0
x este ultima cifra al lui n² ⇒ x= 4,6,5,9,1,0
D={0,1,4,5,6,9}
16
a)
x+3<7 /-3
x<4
A={0,1,2,3}
b)
2³-5>x
8-5>x
3>x
si
x≤3³-2
x≤27-2
x≤25
B={1,2}
x nu poate fi 0 deoarece apartine multimii nr. nat nenule
c)
C={16,25,36,49,64,81}
d)
D={20,22,24,26,28}
e)
E=∅
niciun patrat perfect nu are ultima cifra
f)
2 la puterea x+1
2⁵= 32
⇒x=4
F={4}
