Solve Using substitution.

$\displaystyle x^{3/2}+8x^{1/2}+16x^{-1/2}=0$

$\displaystyle Let A= x^{1/2}$

$\displaystyle A^2+8A+\frac{16}{A}=0$

$\displaystyle A^3+8A^2+16=0$

$\displaystyle A^2(A+8)=-16$

I have no clue if i even did this correctly...Help me please.