We study asymptotic behaviors of positive solutions to the Yamabe equation and the k -Yamabe equation near isolated singular points and establish expansions up to arbitrary orders. Such results generalize an earlier pioneering work by Caffarelli, Gidas, and Spruck and a work by Korevaar, Mazzeo, Pacard, and Schoen on the Yamabe equation and a work by Han, Li, and Teixeira on the k -Yamabe equation. The study is based on a combination of classification of global singular solutions and an analysis of linearized operators at these global singular solutions. Such linearized equations are uniformly elliptic near singular points for 1 k n=2 and become degenerate for n=2 < k n. In a significant portion of the paper, we establish a degree 1 expansion for the k -Yamabe equation for n=2 < k < n, generalizing a similar result for k D 1 by Korevaar, Mazzeo, Pacard, and Schoen and for 2 k n=2 by Han, Li, and Teixeira.