What is 862,840 rounded to

Aregression was run to determine if there is a relationship between hours of tv watched per day (x) and number of situps a person can do (y). the results of the regression were: y=ax+b a=-0.662 b=30.418 r2=0.703921 r=-0.839

Solve for x and select the correct answer

How do you write 600 as a product of its prime factors (index! )