Question

Two times a number decreased by one is between -11 and 13. Find the interval for valid values.

Answer 1

Between -5 and 7.

Explanation:

Let the number be , then:

2x - 1 > -11

and

2x - 1 < 13

First one:

2x - 1 > -11

2x > -11 + 1

2x > -10

x > -5

Second:

2x - 1 < 13

2x < 14

x < 7

So the valid values of x are between -5 and 7.