13) D

We need to rearrange this inequality so that we have 0 on one side and the other figures on the other side.

x² is equal to or more than 8 – 2

Shifting ‘8 – 2x‘ to the other side, we have:
x² + 2x – 8 is equal to or more than 0
Now we factorise the expression ‘x² + 2x – 8′

It is essential that you understand how to ‘Factorise the middle term’

We get (x+4) (x-2) is greater than or equal to 0
Solutions: x is less than or equal to -4 and x is greater than or equal to 2