The couple is simplified easily with the help of left hand rule. But the forces simplification is not possible as there is no such system of rules so that the forces can be simplified.

Force System Resultants topics include: Moment of a force and couple, moment of a force on simplified axis, simple distributed loading, force and couple system simplification. A force system resultant is a representative force that has the same effect on a body as the group of forces it replaces. It is the simplest force that can replace the original forces system without changing its external effect on a rigid body.  The resultant force is the sum of all the vector forces being applied to an object. It is the total amount of force acting on the object or body along with the direction of... Show more

Force System Resultants topics include: Moment of a force and couple, moment of a force on simplified axis, simple distributed loading, force and couple system simplification.

A force system resultant is a representative force that has the same effect on a body as the group of forces it replaces. It is the simplest force that can replace the original forces system without changing its external effect on a rigid body. 
The resultant force is the sum of all the vector forces being applied to an object. It is the total amount of force acting on the object or body along with the direction of the body. 
The resultant force is zero when the object is at rest or it is traveling with the same velocity as the object. 
The magnitude of the resultant force is equal to the total area A under the loading diagram for length L. 
The resultant of a noncoplanar force system is a force R and a couple M, where R = ∑ F, the vector sum of all forces of the system. 

Examples of force systems include:
Forces system on lifting a weight with a pulley system
System on a balanced plank at a pivot 

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