You will almost certainly have to retake them -- everyone does. I don't know of any program (not even the GSB, which arguably has the most flexible one of all) that lets you "skip" Econ - whether or not you get a C+ or an A+ ....
It doesn't sound like your overall GPA is low. In which case, I wouldn't worry about it.
I skipped Econ, but then again I have a masters in Econ, rather than a few classes. In your situation it will make little difference and you will need to sit them at school. You can normally only waive out of the main things (fundamentals of accountancy if you have a CPA, for example).
I think the point that I mean to make is that resitting it will not get you out of doing the classes at school. Resitting it may make you appear like yr grades are better. To add something to your application you would be better to supplement with something you haven't done before that is applicable, if take any classes at all.
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