let * be a binary operation defined on the set of real numbers by a*b=2ab
obtain the inverse of an element x
if b is the inverse, then a*b = 1
2ab = 1
b = 1/(2a)
check:
a*(1/(2a)) = 2a(1/(2a)) = 1
obtain the inverse of an element x
2ab = 1
b = 1/(2a)
check:
a*(1/(2a)) = 2a(1/(2a)) = 1