Problem:

Determining whether the first word from each string in column A appears within the corresponding string in the same row of column B.

Solution:

Use the IF, ISNUMBER, FIND, and LEFT functions as shown in the following formula:
=IF(ISNUMBER(FIND(LEFT(A2,FIND(\" \",A2)-1),B2)),\"1st Word Found\",\"1st Word Not Found\")