I am a mathematician by profession having Msc. in Pure mathematics and BSc. in mathematics. I have a three years experience in writing and one year experience in using latex to write mathematics content using latex. I therefore assure you quality work.
Since we are not allowed to attach anything at this bidding stage, i will provide the codes here.
\documentclass[a4paper,12pt]{article}
\usepackage{amsmath,amsfonts, amssymb,amsthm,epstopdf,array}
\begin{document}
\begin{align*}
8x-3y&=9\\
-3y & = -8x+9\\
y &= \frac{8}{3}x - 3
\end{align*}
\end{document}