Question

Arătați ca A ⊂ B, unde:​

Answer 1

Explicație pas cu pas:

a) A = {10; 11; 12; 13; 14}

B = {7; 8; 9; 10; 11; 12; 13; 14}

=> A ⊂ B

b) A = {2; 3; 6; 9}

B = {1; 2; 3; 6; 9; 18; 27; 54}

=> A ⊂ B

c) A = {1; 2; 4; 8}

B = {1; 2; 4; 8}

=> A = B

d) -5 < x + 3 < 5 <=> -8 < x < 2

A = {-7; -6; -5; -4; -3; -2; -1; 0; 1}

-7 ≤ x ≤ 7

B = {-7; -6; -5; -4; -3; -2; -1; 0; 1; 2; 3; 4; 5; 6; 7}

=> A = B

e) 4x + 11 > 67 <=> 4x > 56 => x > 14

A = {15; 16; 17; ...}

7x - 5 ≥ 72 <=> 7x ≥ 77 => x ≥ 11

B = {11; 12; 13; 14; ...}

=> A ⊂ B

f) (x²-3) ∈ {1; 2; 11; 22}

x²-3 = 1 <=> x² = 4 => x = 2

x²-3 = 2 <=> x² = 5 => x ∉ N

x²-3 = 11 <=> x² = 14 => x ∉ N

x²-3 = 22 <=> x² = 25 => x = 5

A = {2; 5}

-5 ≤ x ≤ 5

B = {-5; -4; -3; -2; -1; 0; 1; 2; 3; 4; 5}

=> A ⊂ B