Question

-12 < 7x + 9 < 16

What is the solution?

Answer 1

-3<x<1

(-3,1)

Explanation:

1. subtract 9 to all 3 sides to get -21<7x<7
2. divide by 7 on all 3 sides to get -3<x<1

it is shown as (-3,1) because x is anything inbetween -3 and 1 and those numbers are not included so you use ( ) as opposed to [ ]

Answer 2

solution :
-3 < x < 1