How do you write 7,870 in scientific notations ?

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?

Let f(x) = 3 − x . find the average rate of change of f(x) from x = a to x = a + h and simplify your answer so that no single factor of h is left in the denominator.

How to simply and write the answer n a whole number