\documentclass{article}
\usepackage{iftex}
\usepackage{ifthen}
\usepackage{epsfig}
\usepackage[utf8]{inputenc}
\usepackage{xcolor}
\ifPDFTeX
\usepackage{newunicodechar}
  \makeatletter
    \def\doxynewunicodechar#1#2{%
    \@tempswafalse
    \edef\nuc@tempa{\detokenize{#1}}%
    \if\relax\nuc@tempa\relax
      \nuc@emptyargerr
    \else
      \edef\@tempb{\expandafter\@car\nuc@tempa\@nil}%
      \nuc@check
      \if@tempswa
        \@namedef{u8:\nuc@tempa}{#2}%
      \fi
    \fi
  }
  \makeatother
  \doxynewunicodechar{⁻}{${}^{-}$}% Superscript minus
  \doxynewunicodechar{²}{${}^{2}$}% Superscript two
  \doxynewunicodechar{³}{${}^{3}$}% Superscript three

\fi
\pagestyle{empty}
\begin{document}
$ b^z = b^x + b^y $
\pagebreak

$ b^z = b^x(1 + b^{y-x})     = b^y(1 + e^{x-y}) $
\pagebreak

$ z   = x + log_b(1 + b^{y-x}) = y + log_b(1 + b^{x-y}) $
\pagebreak

$ y > x, z = y + logadd\_table[-(x-y)] $
\pagebreak

$ x > y, z = x + logadd\_table[-(y-x)] $
\pagebreak

$ logadd\_table[n] = log_b(1 + b^{-n}) $
\pagebreak

$ log_b(2.0) $
\pagebreak

$ y = x $
\pagebreak

$ z = log_b(2x) = log_b(2) + x $
\pagebreak

$ log_b(x+y) = x = y $
\pagebreak

\end{document}
