Which two charges have a sum of 0?
a +6 charge and +6 charge
b −6 charge and −6 charge
c +6 charge and 0 charge
d +6 charge and −6 charge

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.

Which of the following circles have their centers on the x-axis? check all that apply.

Zach spent 2/3 hour reading on friday a 11/3 hlurs reading on saturday. how much more time did he read on saturday tha on friday