Find the vertices of the ellipse x^2/36 + y^2/12 = 1?

This graph has a horizontal major axis. Therefore, a = sqrt(36) = 6, so the vertices are (6,0) and (-6,0) and a vertical minor axis so b = sqrt(12) = 2sqrt(3), so those vertices are (0,2sqrt(3)) and (0,-2sqrt(3)).