The number of roots of s3 + 5 s2 + 7s + 3 = 0 in the right

The number of roots of s³ + 5 s² + 7s + 3 = 0 in the right half of the s-plane is

Number of roots of s³ + 5s² + 7s + 3 = 0 in the LHS of s-plane

Since no sign change, hence no root in RHS of splane.