Why is my credit score different on my Capital One account than it is on Credit Karma?

My Credit score tracker on my Capital One credit card account says that my score is 710. I thought that was good enough to apply to get pre-approved for a mortgage. I haven't had credit for very long since I was using debit for a long time but I have no debts and pay my bills in full on time. Then I checked my scores on Credit Karma and was discouraged.

On Credit Karma is says my transunion score is 582, and my Equifax score is 648.

How can I possibly know what my credit score really is when I am seeing 3 different scores? Does it even matter that I have a 710 if my other two scores are so crappy? I just need a little help understanding this. It seems like I should not be applying to get pre-approved for a mortgage right now.

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