1. The problem statement, all variables and given/known data Please refer to the attached diagram. I am trying to find the unknown load F (along line of action lF) that will keep the system in equilibrium as well as compute all reaction forces developed at the joints. 2. Relevant equations Summation of forces in the horizontal and vertical direction as well as moments about a point. 3. The attempt at a solution I have split the mechanism into these members: Member AB, Member BC, Member CDE, Member DF and Member FG as well as the slider. From these members I can derive the following equations. For: Member AB - 3 equations (summation of forces in horizontal and vertical direction and moments) Member BC - 3 equations Member CDE - 3 equations Member DF - 3 equations Member FG - 3 equations Slider E - 2 equations (summation of forces in horizontal and vertical direction) Total number of equations = 17. However I have 16 unknown parameters which are: Joint A (Ax, Ay) Joint B (Bx, By) Joint C (Cx, Cy) Joint D (Dx, Dy) Joint E (Ex, Ey) Joint F (Fx, Fy) Joint G (Gx, Gy) Unknown force F (along line of action lF) Slider reaction Sy Clearly I need the same number of Unknown parameters and equations to solve. What am I doing wrong?