I am trying to recreate the following using (Lua)LaTeX:\
![image.png](/image?hash=9a4d6b133737852e8c7e9ffa605e0c6a2f6e812ff521fc600e7608a9ed6a53e1)

My current header is
```latex
\documentclass[oneside, leqno, 12pt, a4paper]{book}
\usepackage[text={4.8in,7.4in}, top=2in]{geometry}
\usepackage[greek, french]{babel}
\usepackage{amsmath}
\usepackage{needspace}
\usepackage{changepage}
\usepackage{fontspec}
\usepackage[math-style=french, bold-style=upright]{unicode-math}
\setmainfont{XITS}
\setmathfont{XITS Math}

```

My current code for the math is:
```latex
\begin{equation}
	\left\{
	\begin{aligned}
		\eta = \frac{1}{2\pi } \int_{0}^{\infty} \biggl\{ & \left[\int_{-\infty}^{\infty} F_1(\alpha ) \sin K\alpha d\alpha  - \frac{1 }{S} \int_{-\infty}^{\infty} F_2(\alpha )\cos K\alpha d\alpha  \right]\sin(Kx-St)                               \\
		+                                                 & \left[\int_{-\infty}^{\infty} F_{1}(\alpha )\cos K\alpha d\alpha +\frac{1}{S }\int_{-\infty}^{\infty} F_{2}(\alpha ) \sin K\alpha d\alpha \right] \cos (Kx-St) \biggr\}dK,
	\end{aligned}
	\right.
\end{equation}

```
Which gives me:

![image.png](/image?hash=f81fcd9375ceaefa42d29041fc1f03c04327a94828278bfec7e28c1fe5e8a996)

How can I make sure that the equation numbers end up on the left side and the equation remains centred?