Question

n=? ; n aparține N
a) 1/9 < (n+1)*2/27 < 2/3
b) 2/9 < (n-1)*2/18 < 5/6
c) 11/6 > (2n -3)*2/24 >3/4

Rezolvare completă va rog , dau coronița si rate 5 stele URGENT !!!

Answer 1

Răspuns:

Explicație pas cu pas:

a) 1/9 < (n+1)*2/27 < 2/3

inmultim cu 27

3 < 2(n + 1)  <9

impartim la 2

3/2  < n + 1  < 9/2

scadem 1

3/2 - 1  < n  < 9/2 - 1

1/2  < n  < 7/2

n = 1, 2, 3

_____________

b) 2/9 < (n-1)*2/18 < 5/6

4 < 2(n - 1) < 15

2 < n - 1 < 15/2

3 < n < 17/2

n = 4, 5, 6, 7, 8

_______________

c) 11/6 > (2n -3)*2/24 >3/4

44 > 2(2n - 3) > 18

22 > 2n - 3 > 9

25 > 2n > 12

25/2 > n > 6

n = 7, 8, 9, 10, 11, 12