Mia is three years older than twice her sister brooke age the sum of their ages is less than 30 what is the greatest age brooke can be

What is the number 321,000,000 in scientific notation? also what is the number? ?

Me asap! what is the slope of this line? enter your answer in the box.

Aword processing program requires a 7- digit registration code made up of the digits 1,2,4,5,6,7 and 9 each number has to be used and no number can be used mor than once how many codes are possible