Depends: cuda-7-5 (= 7.5-18) but it is not going to be installed

The following packages have unmet dependencies:
cuda : Depends: cuda-7-5 (= 7.5-18) but it is not going to be installed
unity-control-center : Depends: libcheese-gtk23 (>= 3.4.0) but it is not going to be installed
Depends: libcheese7 (>= 3.0.1) but it is not going to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

I have tried the solution:

1.sudo apt-get remove nvidia-cuda-* # remove old nvidia-cuda packages

2.Install unmet dependencies:

3.Install and use aptitude

4.sudo dpkg -i cuda-repo-ubuntu1404_7.5-18_amd64.deb
sudo apt-get update
sudo apt-get install cuda

but they can’t word! please help me