5(3+4x)-6>=129

Question

I get 2 different answers on this one.

15+20x-6>=129
15+20x-6+6>=129+6
15+20x>=135
15-15+20x>=135-15
20x>=120
20x/20>=120/20
x>=6
Is this worked out properly, are there any shortcuts?

Answer 1

5(3+4x)-6>=129
15+20x-6>=129
9+20x>=129
20x>=120
x>=6