Answer :

Youre just taking away 1x so 7x-1x = 6x 
TSO
[tex]\bf{7x-x}[/tex]

We can take out x as a factor

[tex]\bf{x(7-1}[/tex]

What is 7-1=?

6 !

So then that means

[tex]\bf{x(6)=6x}[/tex]

So your final answer is

[tex]\boxed{\bf{6x}}[/tex]