can someone solve this question step by step I want to learn how to solve.

[ssamiiiii]

How many ways can 12 people line up if Tony, Joe, and Sammie can not be next to each other?

 

[Harry_the_cat]

What have YOU tried? A hint: Fine how many ways 12 people can line up if Tony, Joe and Sammie ARE next to each other?

 

[pka]

How many ways can 12 people line up if Tony, Joe, and Sammie can not be next to each other?

Nine people create ten places to put three people to separate them.