Someone please help me with this

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

Find the number of real number solutions for the equation. x2 + 5x + 7 = 0 0 cannot be determined 1 2

The population of a small rural town in the year 2006 was 2,459. the population can be modeled by the function below, where f(x residents and t is the number of years elapsed since 2006. f(t) = 2,459(0.92)