如何更改此代码中的字体颜色？

Question

\documentclass[12pt, french]{article}
\usepackage{lmodern}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{mathrsfs}
\usepackage{amsthm}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage[utf8]{inputenc}
\usepackage[margin=3cm]{geometry}
\usepackage[x11names]{xcolor}
\usepackage{framed, etoolbox}
\colorlet{framecolor}{VioletRed4}



\begin{document}




        Soit f une application linéaire alors:
    \[\forall x,y\in G,\ f(x)=f(y)\iff x=y\]


\end{document}

Answer 1

\documentclass[12pt, french]{article}
\usepackage{lmodern}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{mathrsfs}
\usepackage{amsthm}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage[utf8]{inputenc}
\usepackage[margin=3cm]{geometry}
\usepackage[x11names]{xcolor}
\usepackage{framed, etoolbox}
\colorlet{framecolor}{VioletRed4}



\begin{document}

\color{blue}%%change the color name what you want



        Soit f une application linéaire alors:
    \[\forall x,y\in G,\ f(x)=f(y)\iff x=y\]


\end{document}

Answer 2

参考了 leandriis如何给数学符号着色？

并做出了如下效果：

\documentclass[12pt, french]{article}
\usepackage{lmodern}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{mathrsfs}
\usepackage{amsthm}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage[utf8]{inputenc}
\usepackage[margin=3cm]{geometry}
\usepackage[x11names]{xcolor}
\usepackage{framed, etoolbox}
\colorlet{framecolor}{VioletRed4}

\usepackage{xcolor}

\begin{document}




        Soit f une application linéaire alors:
    \[\color{red} \forall x,y\in \textcolor{blue}{G},\ f(x)=f(y)\iff x=y\]


\end{document}

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