Question

oxygen boils at -185°c, this is approximately how much?

Answer 1

The rate of degrees m = F/C = 180/100 = 1.8 deg F/deg C between freezing and boiling. 

So from the straight line general equation we can write F = m C + b = 1.8 C + 32, where F = 32 = b deg F when C = 0 deg C, the two freezing points. 

And there, we've just derived the equation for finding F from C. Using the physics. As it should be learned. 

Now you just plug and chug the derived equation. When C = - 183 deg, we have F = 1.8*(-183) + 32 = -297.4 deg F, which is the same as the other answer, but now you know why. Now you know the physics.