Question

va rog cat de repede se poate , ajutati ma la algebra​

Answer 1

Răspuns:

A si B-finite

C si D-infinite

Answer 2

Răspuns:

Explicație pas cu pas:

A = {x  I x ∈ N ; 5x+4 = 19}

5x+4 = 19 => 5x = 19-4 => 5x = 15 => x = 15:5 => x = 3

A = {3} = multime finita

B = {x I x ∈ N , x -7 < 3}  

x-7 < 3 => x < 7+3 => x < 10 => x ∈{0,1,2,3,4,5,6,7,8,9}

B = {0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9} = multime finita

C = {x I x = 3n ; n ∈ N}

n = 0 => x = 3·0 = 0

n = 1 => x = 3·1 = 3

n = 2 => x = 3·2 = 6 .......

C = {0 , 3 , 6 , 9 .......} = M3 = multime infinita

D = {x I x = 3n+2 , n ∈ N}

n = 0 => x = 3·0+2 = 2

n = 1 => x = 3·1+2 = 5

n = 2 => x = 3·2+2 = 8

n = 3 => x = 3·3+2 = 11 ......

D = {2 ; 5 ; 8 ; 11 ; 14 ; 17 ; .......} = multime infinita