Consider a rectangular plate supported at points A, B, and C and subjected to external forces. The forces and couple moments acting on the plate can be reduced to the equivalent resultant force and resultant couple moment acting at point A. Here the line passing through points A and B is not parallel to the y-axis. The equations of equilibrium of the plate can be described using the alternative set of equations. The first equation is satisfied if the resultant force has no x-component and is parallel to the y-axis. The second equation is satisfied if the resultant moment at point A is zero. The third equation states that the moment at point B is zero, which implies that the y-component of the resultant force on the system is zero. A second set of alternative equilibrium equations states that the sum of moments at points A, B and C is zero. These equations are satisfied when these points are not collinear.