Does (-7, 2) make the equation y = x true?

(don't send a link just tell me the answer)

An automated water dispenser fills packets with one liter of water on average, with a standard deviation of 5 milliliter. the manual says that after a year of operation the dispenser should be tested to see if it needs recalibration. a year later a number of filled packets are set aside and measured separately. it is found that the average packet now contains about 0.995 liters. does the dispenser need calibration? explain your answer.

The sum of two numbers is 86, and their difference is 20. find the two numbers

Combine the information in the problem and the chart using the average balance method to solve the problem.