What is n(a u b) in rectangular coordinate system

Use the phrase ""is equal to"" in your own sentence.

Eric practice swimming three days in a week. last week, he practiced 1.38 hours on monday, 1.308 hours on wenesday, and 1.3 hours on sunday. in what day did eric spend more time last week to practice?

What is the distance from the tip of the small finger and the thumb when the hands are spread out and used by the early egyptians to measure objects​