f(x) =5-3x
g(x)=x²-1
f(g(x)) = f(x²-1)
replacing x by x²-1 in the function f(x) , we get
f(x²-1) = 5-3(x²-1) = 5-3x²+3 =8-3x²
f(g(x)) =8-3x²
now finding g(f(x))
g(5-3x)
replacing x by 5-3x in the function g(x)
g(5-3x) = (5-3x)²-1
g(5-3x) = 5²-30x +9x²-1 = 9x²-30x +24
g(f(x))= 9x²-30x +24
f(g(x)) =8-3x²
in option third the f(g(x)) is -3x³+8 which is incorrect
