Hello,
iMC Basic base licenses and any other base licenses, like JG747AAE Standard or JG748AAE Enterprise, cannot be combined. Only one base license can be registered on one installation (Serial Number).
I should also mention that iMC Basic edition is only intended for small installations up to 50 devices that will not need more devices managed than that, and as such, the +50 additional device licenses (JG749AAE) cannot be used in combination with this edition. Only Standard/Enterprise editions can have their device count expanded.
Please check with your HPE Sales contact or reseller about returning the second 50-device license if you only need up to 50 devices, or otherwise returning both and purchasing Standard edition with a +50 additional license instead.