Given that f(x)=x^2, g(x)=x^2+8x, and h(x)=9x find f∘g∘h=

Given that f(x)=x^2, g(x)=x^2+8x, and h(x)=9x

find f∘g∘h= 

Simplify your answers as much as possible

My attempt:

f(x^2))g(x^2+8x)))h(9x)))

x^2+8x+9x

x^2+4x*4x*3x*3x

x^2+(16x)^2+(9)^2

=x^2+256x+81 

I've been struggling with the order of the composition of functions for a while so I'd be extremely grateful if anyone could please explain it to me!

Thank you in advance!