For this case we must find an expression equivalent to:
[tex]10q-30[/tex]
We look for the factors of 10 and 30:
10: 1,2,5,10
30: 1,2,3,5,6,10,15,30
The greatest common factor of both numbers is 10.
Then, we can rewrite the expression as:
[tex]10 (q-3)[/tex]
Answer:
[tex]10 (q-3)[/tex]