To evaluate the expression \(-2.5g + 26.4\) for \(g = 14.7\), we can substitute 14.7 for \(g\):
\[ -2.5(14.7) + 26.4 \]
Now we calculate \(-2.5 \times 14.7\):
\[ -2.5 \times 14.7 = -36.75 \]
Next, we add 26.4 to \(-36.75\):
\[ -36.75 + 26.4 = -10.35 \]
So, the evaluated expression is:
\[ \boxed{-10.35} \]