11 Seven less than a number is 15 You can help me.

How can you decide witch operations to use to slice a two step equation

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.

Identify this conic section. x2 - y2 = 16 o line circle ellipse parabola hyperbola