数组之间的换行

Question

我有这些值列表，但它们都挤在一起，如何在它们之间添加新行？我试过 \ 和 \newline 等各种方法，但都会出错。谢谢！

\documentclass[a4paper,12pt]{article}
\usepackage{amsmath}
\usepackage{parskip}
\usepackage{graphicx}
\usepackage{caption}
\usepackage{array}

\begin{document}
  \centerline{Question 2}

    $x = \begin{array}{@{} *{3}{>{$}p{9em}<{$}} }
    -1.5  & -0.5 &  -0.804163391778384
    \end{array}$

    iteration = \hspace{8mm}1

    $x = \begin{array}[t]{@{} *{3}{>{$}p{9em}<{$}} }
    -1.5  & -0.5 &  -0.804163391778384  \\
    -0.805017312865838  &   &
    \end{array}$

    iteration = \hspace{8mm}2

    $x = \begin{array}[t]{@{} *{3}{>{$}p{9em}<{$}} }
    -1.5  & -0.5 &  -0.804163391778384  \\
    -0.805017312865838  &  -0.804950125594231
    \end{array}$

    iteration = \hspace{8mm}3

    $x = \begin{array}[t]{@{} *{3}{>{$}p{9em}<{$}} }
    -1.5  & -0.5 &  -0.804163391778384  \\
    -0.805017312865838  &  -0.804950125594231 &-0.804950131975765
    \end{array}$

    iteration = \hspace{8mm}4

    root = \\
    $-0.80495$
\end{document}