Question 1031181
Find the functions f ○ g and g ○ f. 
f(x)=5x-9 ; g(x)=1/5(x+9) 

(f ○ g)(x) = f[g(x)] = f[(1/5)(x+9)] = 5[(1/5)(x+9)]-9 = x

(g ○ f)(x) = g[f(x)] = g[5x-9] = (1/5)(5x-9+9) = x
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Comment:: That means f and g are inverse to one another.
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Cheers,
Stan H.
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