We are asked to convert -129 F to Celsius. To do that we will use the following formula:
[tex]C=\frac{5}{9}(F-32)[/tex]Where:
[tex]\begin{gathered} C=\text{ reading in Celsius} \\ F=\text{ reading in Fahrenheit} \end{gathered}[/tex]Now we plug in the reading in Fahrenheit:
[tex]C=\frac{5}{9}(-129-32)[/tex]Solving the operations:
[tex]C=-89.44\text{Celsius}[/tex]Therefore, the Celsius reading is -89.44°C.