Error solving equation in CAS

[DrD]

Perhaps a hint here is that after copy/pasting this expression from your text into EMU/CAS (Var X:=0 in this example):

((3.068E-3/(0.118+1.001E-5*X))-(((1+2.126E-5*X)/(1+8.506E-5*X))-(0.3+2.55E-5*X)))=0

The EMU/CAS Entry line resulted in this:

$$
\left(\frac{3.068e-3}{0.118+1.001e-5*X}
{-}
\left(\frac{1+2.126e-5*X}{1+8.506e-5*X}
{-}
\left({0.3+2.55e-5*X}\right)
\right)\right)
{=0}
$$

EMU/CAS then produced this output:

$$
\left({-.674}\right){=0}
$$

Exactly approximate and vice versa!