Question

Determinați mulțimile :
A={x € N / (3x-1) I 48}
B={x € N / x= 4a2b ,x este divizibil cu 5 si a=b+3}
Dau Coronița

Answer 1

Multimea A
(3x+1)l48=>(3x+1)€Divizori 48
D48= {1;2;3;4;6;8;12;16;24;48}
1. 3x+1=1
x=0
2.3x+1=2
x=1 / 3 Fals
3.3x+1=3
x=2/3 fals
4.3x+1=4
x=1
5.3x+1=6
x=5/3 fals
6.3x+1=8
x=7/3 fals
7.3x+1=12 fals
8.3x+1=16
x=5
9.3x+1=24 fals
10.3x+1=48 fals
A={0,1,5}

Multimea B

x e multiplu de 5 =>b=0 sau 5
1.b=0
a=3=>x=4320(daca era cu bara) sau daca era inmultire x=4*3*2*0=0
2.b=5
a=8=>x=4825(daca era cu bara)sau daca era inmultire x=4*8*5*2==32*10=320