Displacement of a steel rod - don't know how to begin

[pleasehelpme6]

The A-36 steel rod is subjected to the loading shown.

If the cross-sectional area of the rod is 50 mm^2, determine the displacement of C.
Neglect the size of the couplings at B, C, and D.

Please help, I don't have any idea how to begin. I can't seem to sum the forces right.

 

[PhanthomJay]

It is best to look at each force separately, find the displacement at C under each force, and then add up the results. You have to know the modulus of elasticity of the steel, and the displacemnt formula. Note that under the 9 N force, point C just goes along for the 'ride'.