What is the equation of the least squares regression line for the data set?

7. if the value of x varies directly with the value of y, and x = 3 when y = 21. what is the valu y, and x = 3 when y = 21. what is the value of x when y = 105?

Adam used 1072.4 gallons of water over the course of 7 days. how much water did adam use, on average, each day?

The? half-life of a radioactive substance is 20 years. if you start with some amount of this? substance, what fraction will remain in 120 ? years