Answer
$14^oF \text{ to } \left( \dfrac{322}{5} \right)^oF$
Work Step by Step
Using $C=\dfrac{5}{9}(F-32),$ then the equivalent range of Fahrenheit values for $-10^oC$ to $18^oC$ is
\begin{array}{l}\require{cancel}
-10\le\dfrac{5}{9}(F-32)\le18
.\end{array}
Using the properties of inequality, then
\begin{array}{l}\require{cancel}
\dfrac{9}{5}\left( -10 \right) \le\dfrac{9}{5}\cdot\dfrac{5}{9}(F-32)\le\dfrac{9}{5}\cdot18
\\\\
-\dfrac{90}{5} \le F-32\le\dfrac{162}{5}
\\\\
-\dfrac{90}{5}+32 \le F-32+32\le\dfrac{162}{5}+32
\\\\
-\dfrac{90}{5}+\dfrac{160}{5} \le F-32+32\le\dfrac{162}{5}+\dfrac{160}{5}
\\\\
\dfrac{70}{5}\le F\le\dfrac{322}{5}
\\\\
14\le F\le\dfrac{322}{5}
.\end{array}
Hence the equivalent range of temperature in Fahrenheit is $
14^oF \text{ to } \left( \dfrac{322}{5} \right)^oF
.$