Answer :
separate 75 into two numbers. Lets use 15 and 5. 15 can be reduced into 3 and 5, while 5 cannot be reduced. The remaining numbers you have will be 5, 5, and 3.
75
/ \
15 5
/ \
3 5
75
/ \
15 5
/ \
3 5
Like this-
. 75
. /. \.
. 25. 3
. /. \.
. 5. 5.
So the factors are- 3x5x5.
Hope I helped!