First, treat it like an equation:
y = 3x + 1
This is in the form y = mx + b.m is the slope and b is the y intercept. In this case, the slope is 3 and the y intercepts is + 1. That means it'll start at +1 and for every increase in x , y will increase by 3 and for every decrease in x , y will decrease by 3.
This is what 3x-1 looks like:
graph{y=3x-1 [-10, 10, -5, 5]}
Now we want the part of the graph that is greater than that. That means we shade above it. This would be your final graph:
graph{y>=3x-1 [-10, 10, -5, 5]}
