Hi
1) f(x)= 0.9 x
2) g(x) = x-100
3) f °g. is first apply g then f. so :
f°g = 0.9 ( x-100) = 0.9x-90
4) g°f. is first apply f then g
so g°f = (0.9x) -100 = 0.9x-100
I let you conclude which is the best deal :)
