Question

1. Determinații mulţimile: A={x E N \ 4x < 2x + 6} B={x E N* \ 7x < 3x + 12} C={x E N | 8x = 5x + 3}​

Answer 1

4x < 2x+6

4x-2x < 6

2x < 6

x < 6/2

x < 3 ⇒ A={0,1,2}

7x < 3x +12

7x -3x < 12

4x <12

x < 12/4

x < 3 ⇒ B={1,2}

8x = 5x+3

8x-5x = 3

3x = 3

x = 1 ⇒ C={1}