Hello.
First, "half a number" means we divide that number by 2.
Let's say the number is z.
Divide z by 2:

Add 5 to it:

Now, this expression equals 11:

Subtract 5 from both sides:


Now, in order to get rid of the fraction, we should multiply the entire equation by 2:



I hope it helps.
Have an outstanding day. :)
