C+c=

The expression "c+c" cannot be simplified or solved without knowing the values of the variables involved. In algebraic terms, it represents the sum of two variables denoted by 'c'. If you have specific values for 'c', you can simply add them together. For example, if c=4, then c+c=4+4=8. However, without any further information or context, it is not possible to provide a specific answer.