Below is my code. I have tried using the arraystretch but it is not working well for my document since it affects all the tables and matrices I dont want to adjust. I also tried some techniques from this link Using display style fraction in a matrix environment but I failed to achieve the results I want.
\documentclass[11pt,oneside,openany]{book}
\usepackage[a4paper, left=1.5cm, right=1.5cm, top=3cm, bottom=3cm]{geometry}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\begin{document}
\begin{alignat*}{2}
\begin{bmatrix}
5 & 6 & 7 \\
0 & 2 & \\
4 & 8 &
\end{bmatrix}&=\begin{bmatrix}
\frac{327}{78} & \frac{132}{7} & \frac{312}{17} \\
\frac{32}{7} & \frac{32}{7} & \\
\frac{32}{7} & \frac{32}{7} &
\end{bmatrix}+&\begin{bmatrix}
\frac{10}{7} & \frac{10}{7} & \frac{10}{7} \\
-\frac{25}{7} & -\frac{25}{7} & \\
\frac{10}{7} & \frac{10}{7}&\end{bmatrix}+&\begin{bmatrix}
-1 & 0 & 1 \\
-1 & 1 & \\
-2 & 2 &
\end{bmatrix}
\end{alignat*}
\end{document}
