check up vs inquire

check up

verb
  • To seem correct or plausible; to comport with known facts; to check out (with other facts). 

  • I dropped by to check up on my friend. 

  • To verify through brief investigation or revisit for assurance that there are no problems. 

  • To verify something's accuracy. 

inquire

verb
  • To make an inquiry or an investigation. 

  • To ask (about something). 

How often have the words check up and inquire occurred in a corpus of books? (source: Google Ngram Viewer )