What I'm doing was correct?

Answer:
The distance between points R and S is [tex]\sqrt{ 29 }[/tex] units
Step-by-step explanation:
Coordinates of point R = (-1, 3)
Coordinates of point S = (4, 1)
Now, by distance formula:
[tex]d(R, S) = \sqrt{ \{4 -( - 1) \}^{2} + {(1 - 3)}^{2} } \\ \\ = \sqrt{ \{4 + 1 \}^{2} + {( - 2)}^{2} } \\ \\ = \sqrt{ \{5 \}^{2} + {( - 2)}^{2} } \\ \\ = \sqrt{ 25 + 4 } \\ \\ \implies \huge \orange{d(R, S) = \sqrt{ 29 } \: units}[/tex]
So, you are correct.