A method for semi-rectifying algebraic and differential systems using scaling type Lie point symmetries with linear algebra We present two new algorithms based on Lie symmetries that respectively allow to semi-rectify algebraic systems and reduce the number of parameters on which the steady points of a differential system depend. These algorithms facilitate the qualitative analysis of algebraic and differential systems. They are designed with a strong view towards applications, such as modeling in biology. Their implementation, already available in our MABSys package, is of polynomial time complexity in the input size.