Answer
See answer below
Work Step by Step
We are given $S=\{(5,-1,2);(7,1,1)\}$ in $R^3$
Since $dimR^3=3 \rightarrow S$ does not span $R^3$.
Hence, $(5,-1,2);(7,1,1)$ are not proportional which gives us that $S$ is a linearly independent set in $R^3$
