Question

The operation on the set R of real numbers are define by a*b=ab/4+a-b

Answer 1

Determine whether or not the operation * is association

Answer 2

(a*b)*c = (ab/4+a-b)*c
= (ab/4+a-b)c/4+(ab/4+a-b)-c
= abc/16 + (ab+ac-bc)/4 + a-b-c

a*(b*c) = a*(bc/4+b-c)
= a(bc/4+b-c)/4 + a - (bc/4+b-c)
= abc/16 + (ab-ac-bc)/4 + a-b+c

so not associative