Placing three mathematical formulas next to each other

I am new to LaTeX, so please be kind to me. :) I would like to place three mathematical formulas next to each other but I don't seem to get it working.

This is how far I have got up to now:

\documentclass[paper=a4,pagesize,fontsize=12pt]{scrartcl}

\begin{document}

\renewcommand{\arraystretch}{1}
\begin{tabular}{l}
\hspace{1cm} \vspace{0.2cm}
$$\displaystyle \widetilde{y_i}=bx_i+a$$  \hspace{3cm}\\
$\widetilde{y_i}$ \ldots vorhergesagter Wert \\
$b$ \ldots slope (Steigung der Regressionsgerade) \\
$a$ \ldots intercept (Gerade schneidet y-Achse, an der Stelle x=0) \\

\end{tabular}
\vspace{0.22cm}
\begin{center}

\begin{tabular}{cc}
\renewcommand{\arraystretch}{1.5}
\begin{tabular}{l}

$$\displaystyle b=\frac{s_{XY}}{s_X^2}$$ \0.4cm] \end{tabular} \renewcommand{\arraystretch}{1.5} \begin{tabular}{ccc} & $$\displaystyle a=\bar{y}-b\bar{x}$$ & \\ [0.4cm] \end{tabular} \end{tabular} \end{center} \vspace{0.22cm} \end{document} This is what it looks like at the moment: I would like to put the formula for b=sXY... and the formula for a=y-b*x higher up so that it is in the same line with the first formula (y_i= b*x_i+a). I hope that you understand my problem and that someone is able to help me. Thanks a lot already in advance. • Welcome to TeX.SE! Try \documentclass{article} \usepackage{amsmath} \begin{document} \begin{align} b&=\frac{s_{XY}}{s_X^2} & a&=\bar{y}-b\bar{x} \end{align} \end{document} – user121799 Nov 16 '18 at 17:35 • Since you have some responses below that seem to answer your question, please consider marking one of them as ‘Accepted’ by clicking on the tickmark below their vote count (see How do you accept an answer?). This shows which answer helped you most, and it assigns reputation points to the author of the answer (and to you!). It's part of this site's idea to identify good questions and answers through upvotes and acceptance of answers. – user36296 Jan 5 at 12:39 4 Answers Maybe like this: \documentclass[paper=a4,pagesize,fontsize=12pt]{scrartcl} \usepackage{amsmath} \begin{document} Text above \begin{align*} \widetilde{y_i}&=bx_i+a, & b&=\frac{s_{XY}}{s_X^2}, & \displaystyle a&=\bar{y}-b\bar{x}, \end{align*} where \begin{align*} \widetilde{y_i} &\ldots \text{vorhergesagter Wert} \\ b &\ldots \text{slope (Steigung der Regressionsgerade)} \\ a &\ldots \text{intercept (Gerade schneidet y-Achse, an der Stelle x=0)} \end{align*} \end{document} Keep it simple: \documentclass[paper=a4,pagesize,fontsize=12pt]{scrartcl} \usepackage{amsmath} \usepackage{enumitem} \usepackage{showframe} % just to show the page margins \begin{document} \begin{gather*} \tilde{y}_i=bx_i+a \qquad b=\frac{s_{XY}}{s_X^2} \qquad a=\bar{y}-b\bar{x} \\ \begin{minipage}{0.8\displaywidth} \begin{itemize}[label=,nosep,leftmargin=0pt] \item \tilde{y}_i vorhergesagter Wert \item b slope (Steigung der Regressionsgerade) \item a intercept (Gerade schneidet y-Achse, an der Stelle x=0) \end{itemize} \end{minipage} \end{gather*} \end{document} You can later change your mind about the label in the itemize environment. With gather* we ensure no page break is feasible between the equations and their descriptions. Make it easy. See if this way of alignment suit you :) \documentclass{scrartcl} \usepackage{amsmath} \begin{document} Blah blah we have: \begin{align*} \widetilde{y_i}=bx_i+a \qquad\quad b=\frac{s_{XY}}{s_X^2} \qquad\quad a=\bar{y}- b\bar{x} \end{align*} \[ % or  for inline mode if you want \text{where }\left\{ \begin{array}{rcl} \widetilde{y_i} & \ldots & \text{vorhergesagter Wert}\\ b & \ldots & \text{slope (Steigung der Regressionsgerade)}\\ a & \ldots & \text{intercept (Gerade schneidet y-Achse, an der Stelle x=0)} \end{array} \right.
\end{document} Thank you guys all so so much for your much-appreciated help. My document looks really good now. :)

I have one last question: How can I make the

y_i... vorhergesagter Wert,
b...slope,
a...intercept AND
r_i... Residuum,
y_i... beobachteter Wert,
\widetilde y_i... vorhergesagter Wert

make appear aligned under each other. I would like both parts either to be in the center or on the left.

\flushleft \textbf {Die Regressionsgerade:}

\begin{gather*}

\widetilde{y}_i=bx_i+a

b=\frac{s_{XY}}{s_X^2}

a=\bar{y}-b\bar{x}

\\

\begin{minipage}{0.8\displaywidth}

\begin{itemize}[label=,nosep,leftmargin=0pt]

\item $\widetilde{y}_i$ \ldots vorhergesagter Wert

\item $b$ \ldots slope (Steigung der Regressionsgerade)

\item $a$ \ldots intercept (Gerade schneidet $y$-Achse, an der Stelle $x=0$) \\[0.4cm]

\end{itemize}

\end{minipage}

\end{gather*}

\flushleft \textbf {Residuen:}

\begin{center}

\renewcommand{\arraystretch}{1}

\begin{tabular}{l}

\hspace{1cm} \vspace{0.2cm}

$$\displaystyle r_i = y_i - \widetilde{y_i}$$  \hspace{3cm}\\

$r_i$ \ldots Residuum für Beobachtung $i$\\

$y_i$ \ldots beobachteter Wert von Person $i$\\

$\widetilde{y_i}$ \ldots vorhergesagter Wert von Person $i$\\[0.4cm]

\end{tabular}

\end{center}

\vspace{0.22cm}

Thank you so much one more time.

• If you want them to be aligned to the left, why not simply type them as normal text? To make it better, add \qquad in front of each of them. – user156344 Nov 18 '18 at 10:04