#### Answer

The bearing can be expressed as $270^{\circ}$
The bearing can be expressed as $N~90^{\circ}~W$ or $S~90^{\circ}~W$

#### Work Step by Step

The point (-4,0) is located directly to the west from the radar station at the origin.
The bearing can be expressed as $270^{\circ}$. This means the bearing is $270^{\circ}$ clockwise from due north.
The bearing can be expressed as $N~90^{\circ}~W$, which means the bearing is $90^{\circ}$ counterclockwise from due north. The bearing can also be expressed as $S~90^{\circ}~W$, which means the bearing is $90^{\circ}$ clockwise from due south.