Question 1075054
The purpose for (I) must have been to show how the OPERATION (f) is supposed to work.


The purpose of (II) seems unnecessary other than to help to be sure we have used the operation as defined in (I) correctly.


Following the definition for f demonstrated in (I), choice (b) seems to be the result for  (2 f 1); .


III.

2f1=2/1-2(1f2)

=2-2(1/2-2(2f1))

=2-1+4(2f1)

2f1=2-1+4(2f1)

2f1=1+4(2f1)

0=1+3(2f1)

-1=3(2f1)

-1/3=2f1
Corresponding to choice b.