Please help me with this question

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

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.

The sum of these consecutive integers is equal to 9 less than 4 times the least of the integer. find the three integers