The way that it is written is odd.
If the problem was 3(x-5)=30, it would be 3x-15=30.
Add 15 to both sides.
3x=45
Divide both sides by 3.
x=15
If it's supposed to be 3(x-5)<30, your answer would be the same, except:
x<15.
I'm not sure why it has both signs, especially next to each other.
I hope this helps :)