Additive can’t manage to perform (5)
I believe the answer is:
enact
'perform' is the definition.
(thesaurus)
'additive can't manage' is the wordplay.
'additive' becomes 'e' (I can't explain this - if you can you should give a lot more credence to this answer).
'manage' is an anagram indicator (I've seen 'managed' mean this).
'cant' anagrammed gives 'nact'.
'e'+'nact'='ENACT'
'to' is the link.
Can you help me to learn more?
(Other definitions for enact that I've seen before include "Present" , "Put into practice" , "Pass into law" , "Play one's part" , "get into law" .)