Answer: "possible" rational roots: ±1/5, ±3, ±1
Step-by-step explanation: Take plus or minus the factors of the constant divided by the factors of the leading coefficient.
In this case, the constant is 3, so the factors are 1 and 3, and the leading coefficient is 5, so the factors are 5 and 1.
1/5, 3/5, 1/1 and 3/1 are possibilities, simplify and attach the ± to each.