how do I solve F = 5/9 (F-32) ?

Answer 1

I assume this is to calculate where °C and °F are the same?

F = 5/9 F - 5/9 * 32
4/9 F = -5/9 * 32
4F = -*32 = 160
F = -40

And, sure enough, -40°F is the same as -40°C

Answer 2

post it.