Question

Which of the following is a solution of the compound inequality -1 < 2n + 1 < 5? '

-1 < n < 5
n > 2 or n < -1
-1 < n < 2
n < -2 or n > 4

Answer 1

-1 < 2n + 1 < 5

-1 <2n + 1
-1 -1 < 2n + 1 - 1
-2 < 2n
-2/2 < 2n/2
-1 < n

2n + 1 < 5
2n + 1 - 1 < 5 - 1
2n < 4
2n/2 < 4/2
n < 2

so you have n greater then -1 and less then 2.

ANSWER: -1 < n < 2