In a LibreOffice Impress presentation (Version 5.1.4.2 on Ubuntu 16.04), when I click Insert > Object > Formula, I see a visual toolbar that lets me add elements of an equation such as fractions etc. However:
 The inserted formula is in a very small font (18 pt), and I do not find any way to enlarge it, neither within the formula editor nor outside it. Outside the editor, I can enlarge the font of the box, but it has no effect.
 It is very cumbersome to insert formulas through the visual editor. Is there a way to insert formulas in a plain text markup, like in Writer?
Here is Solutions:
We have many solutions to this problem, But we recommend you to use the first solution because it is tested & true solution that will 100% work for you.
Solution 1
###TexMaths
TexMaths is an extension designed to provide LaTeX support in LibreOffice. LaTeX equations can be inserted as images (SVG or PNG formats) and the LaTeX code is saved into the image attribute for further editing. To insert your first equation into a document, simply type a LaTex math instruction in the text field of the TexMaths Equations window and then click on the LaTeX button. Example: x(t) = \mu ^2 (t)
should produce the equation x(t)=µ²(t)
TexMaths is open source software licensed under the GPL.
###Installation

Install TexLive.
sudo aptget install texlive texlivebinaries dvipng

Download the TexMaths extension by following the download link at the official TexMaths website. The file to download ends in an .oxt extension.

Open LibreOffice Writer and install the TexMaths extension using the Tools > Extension Manager menu.

Close and reopen LibreOffice Writer. You will see a four new TexMaths icons in the toolbar. Click on the TexMaths System Configuration icon and fill in the paths of your programs (usually
/usr/bin
for all).
###Usage
 Run TexMaths by clicking on one of the TexMaths Equations icons. Clicking on the first Pi icon which is marked by a black arrow in the below screenshot will open a new TexMaths Equations window. You need to type a group of mathematical symbols in LaTeX format inside the TexMaths Equations window instead of typing it directly on the slide
**Don't do it this way**
**Do it this way**
^{Select either Display or Inline Equation Type. Display looks better than Inline}
After the equation is added to the slide, you can drag it to its correct position on the slide.
 There can be images of mathematical symbols and plain text mathematical symbols together in the same slide, as in the below slide where the large equation in the middle is an embedded image and the highlighted text is plain text.
###Examples
Solution 2
You can easily control the size and color of equation objects in Impress (and any LO apps) using size and color.
For example:
Size 24 color blue { E = m c^2 }
Note: Use and implement solution 1 because this method fully tested our system.
Thank you 🙂
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