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

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....