Finding Work Done by Force (F): Is it Fx or F?

[Miike012]

The question asks.. find the work done by Force (F)...
the answer given was found by the x component of Force (F)... so my question is, is this the work done by F_x or by F?

 

[sandy.bridge]

When dealing with work, the component of force that is parallel to the displacement of the object is used for calculations. Work is equal to the dot product of the force and displacement vectors.