3, 15, 75, 375, 1875
r = common ratio
[tex]r=\text{ }\frac{15}{3}\text{ = }\frac{75}{15}\text{ = }\frac{375}{75}\text{ = }\frac{1875}{375}\text{ = 5}[/tex][tex]\text{ a first term = 3}[/tex][tex]\begin{gathered} y=a(r^{n\text{ - 1}}) \\ \\ y=3(5^{n\text{ - 1}})\text{ This is the exponential function} \\ \end{gathered}[/tex]
