We present a systematic methodology to determine and locate analytically isolated periodic points of discrete and continuous dynamical systems with algebraic nature. We apply this method to a wide range of examples, including a one-parameter family of counterexamples to the discrete Markus-Yamabe conjecture (La Salle conjecture); the study of the low periods of a Lotka-Volterra-type map; the existence of three limit cycles for a piece-wise linear planar vector field; a new counterexample of Kouchnirenko's conjecture; and an alternative proof of the existence of a class of symmetric central configuration of the (1 + 4)-body problem.Mathematics Subject Classification 2010: 37C25, 39A23 (Primary); 13P15, 34D23, 70F15, 70K05 (Secondary).satisfies the Markus-Yamabe condition (2) and has a 3-periodic orbit.Prior to prove this proposition, we recall the following auxiliary lemma, that is a simplified version of a result given in [12]. Lemma 4. Let G(x; b) = g n (b)x n + g n−1 (b)x n−1 + · · · + g 1 (b)x + g 0 (b) be a family of real polynomials that depend continuously on one real parameter b ∈ B = [b 1 , b 2 ] ⊂ R. Fix J = [x, x] ⊂ R and assume that: (i) There exists b 0 ∈ B such that G(x; b 0 ) has no real roots in J.