Some students designed a temperature measuring device, the structure of which is shown in Figure (a). Glass bulb A is sealed with a certain mass of gas, and mercury is inserted into the thin tube B co

Some students designed a temperature measuring device, the structure of which is shown in Figure (a). Glass bulb A is sealed with a certain mass of gas, and mercury is inserted into the thin tube B connected with A.. (1) As can be seen from the image, the functional relationship between the mercury column height x and the ambient temperature t is an inverse ratio image, and the slope K= 75 375 =0.2, so the relationship is x = 75-0.2t；;

(2) The intercept of the vertical axis is atmospheric pressure P0 = 75 cmhg；; ;

(3) The atmospheric pressure p 0' is lower than the above atmospheric pressure P0 1cmHg, so the slope of the image decreases and the measured temperature value is larger. As can be seen from the table, the difference between the measured value and the real value is about 5℃.

So the answer is: x=75-0.2T, 75, too big, 5.