A={x∈N*/ 2x(X-1)≤7}
2x(X-1)≤7
2X-2≤7
2X≤7+2
2X≤9
X≤9:2
X≤4,5
A={1, 2, 3, 4,}
B={y∈N/ y =2^x, x∈A}
y=2^1=2
y=2^2=4
y=2^3=8
y=2^4=16
B={2, 4, 8, 16}
C={z∈N/ z=3x, x∈A}
z=3x1-1=3-1=2
z=3x2-1=6-1=5
z=3x3-1=9-1=8
z=3x4-1=12-1=11
C={2, 5, 8, 11}
Sper ca te-am ajutat! ^^
P.S: Sigur e corect exercitiul? Mi se pare cam ciudat sa fie x≤9:2...