Answer
$-40^{\circ}$
Work Step by Step
1. To calculate the common temperature, we use the equation for conversion
$C=\frac{F-32}{1.8}$
2. Since both values are the same, we can indicate them temperature as x, then just solve for x:
$C=F=x$
$x=\frac{x-32}{1.8}$
$1.8x=x-32$
$0.8x=-32$
$x=-40$
