If you multiply both sides of your equation by (x+1), you will get the equation x^5 + 1 = 0, or x^5 = -1. Its roots are the roots of degree 5 of -1 (one real root -1 and the others are complex roots). Therefore, the roots of the original equation are all four complex roots of the degree 5 of -1. They are 1) cos(36°) + i*sin(36°); 2) cos(108°) + i*sin(108°); 3) cos(252°) + i*sin(252°); 4) cos(324°) + i*sin(324°).