Answer:
![\bf \phi (9)=5](https://tex.z-dn.net/?f=%20%5Cbf%20%5Cphi%20%289%29%3D5)
![\bf \phi (15)=8](https://tex.z-dn.net/?f=%20%5Cbf%20%5Cphi%20%2815%29%3D8)
![\bf \phi (75)=40](https://tex.z-dn.net/?f=%20%5Cbf%20%5Cphi%20%2875%29%3D40)
Step-by-step explanation:
Positive integers relative primes to 9 which are less or equal than 9
{1,2,4,5,7}
so
Positive integers relative primes to 15 which are less or equal than 15
{1,2,4,7,8,11,13,14}
and
Positive integers relative primes to 75 which are less or equal than 75
{1,2,4,7,8,11,13,14,16,17,19,22,23,26,28,29,31,32,34,37,38,41,43,44,46,47,49,52,53,56,58,59,61,62,64,67,68,71,73,74}
and