Dalton's law of partial pressures: The total pressure of a gas mixture is equal to the sum of the partial pressures of the individual gases in the mixture.

$$P_{total} = P_{N_2} + P_{O_2} + P_{CO_2}$$

We are given the following partial pressures:

$$P_{N_2} = 630 \ mmHg$$

$$P_{CO_2} = 39 \ mmHg$$

We can rearrange Dalton's law to solve for the partial pressure of oxygen:

$$P_{O_2} = P_{total} - P_{N_2} - P_{CO_2}$$

Since we are given the total pressure nor the partial pressures, then we can´t solved.