Twice a number is no less than 10 units from -1

Question

How can i write this as an inequality 

Answer 1

X is the number

 

If a value is no less than 10 units from -1, then it is

greater than or equal to 10 units from -1

 

  | 2X + 1 |  ≥ 10          this absolute value can be used to show

                                     the distance between 2X and -1 is ≥ 10

 

solving this inequality

 

   -10 ≥ 2X + 1 ≥ 10     subtract 1 in all three places

 

   -11 ≥ 2X  ≥ 9            divide all three by 2

 

  -5.5 ≥ X  ≥ 4.5

 

those values work for X