# What phase of "CO"_2 exists at -57^@ "C" and "2 atm"?

This is just asking you to use your finger to trace where you are on the phase diagram. Think back to when you learned about graphs. Treat $T$, the temperature, as your $x$ value, and $P$, the pressure, as your $y$ value.
Now point to where $T = - {57}^{\circ} \text{C}$, and $P = \text{2 atm}$. Did you point here?