Just purchased 2008 only 50k on Odo

[Tcx82]

Hi guys, i just purchased an 2008 with only 50k on Odometer for 14k. The car Interior and exterior was in excellent condition and it drive very smooth. But today I noticed a little bit of rusted on the left side and right side of rear wheels, near the brake lines /axels. I'm wonder is that serious? I check the frame there are no rust. I look at the car history look like it from Pennsylvania, so it worry me a bit.

[RX400h]

Is it an RX350 or RX400h? It could be that this vehicle had been sitting in water for a while, but as long as the rust isn't spread throughout the entire undercarriage, and the tire seals to the wheels are good, I wouldn't worry too much about that.

When I looked at a 2002 Mazda Protege for my daughter, way back in 2010, I noticed that some of its suspension bolts and components were rusty. The owner told me that he had the car in New York for a few years before driving it to San Diego, CA. Since the cost was only $5000, I bought it. Over the next 7 years, the only issue that was a result of the rust was an alignment bolt that was impossible to loosen. 
So as long as your alignment adjustments are possible, your minimal rust wouldn't seem to be a problem as long as my first sentence applies.