A metal stays solid at Fahrenheit temp below 1868.5

Determine (in terms of an inequality) those Celsisu temp, for which the metal stays solid. Use the formula

$\displaystyle F=9/5c+32 $

This is what I've got so far:

1868.5 = (9/5)c + 32

multiply by 5

9342.5 = 9c + 160

1020.28

but then I get lost? Is this even right? Help please....