Answer:
2 x − 6
Step-by-step explanation:
"Six less than.." means "Subtract 6 from".
Do not confuse this with "Six less..." which means "Subtract from 6".
Confusing, I know.
We know that "Double a number" means
2 x , where x is your mystery number.
Therefore, we have:
2 x − 6 , which translates to "6 less than 2x" or "6 less than twice a number"