Question

Twice a number, increased by three, is between negative one and eleven

Answer 1

-2 ≤ x ≤ 4

Explanation:

solving the double inequality :

-1 ≤ 2x + 3 ≤ 11

⇔ -1 - 3 ≤ 2x ≤ 11 - 3

⇔ -4 ≤ 2x ≤ 8

⇔ -4/2 ≤ 2x/2 ≤ 8/2

⇔ -2 ≤ x ≤ 4