
Robert J. answered 12/02/13
Certified High School AP Calculus and Physics Teacher
f(g(x))
= (5g(x)-3)/(2g(x)+1)
= [5(x+3)-3(5-2x)]/[2(x+3)+(5-2x)], after multiplying by (5-2x)/(5-2x)
= 11x/11
= x
g(f(x))
= (f(x)+3)/(5-2f(x))
= [(5x-3)+3(2x+1)]/[(5(2x+1)-2(5x-3)], after multiplying by (2x+1)/(2x+1)
= 11x/11
= x
So, f(x) and g(x) are inverses.