If a house was priced at &98,000 and grows at 4% per year, what will
be the future median home selling price in eight years?   What amount
will I have to accumulate as a down payment if I decide to buy a
house?

There is not enough data to answer the questions.  There are houses in
all price ranges.  What does the particular house mentioned in the
question have to do with the median price of all houses?  As for the
down payment you will need to accumulate, it depends on the price of
the house you buy and what percentage of the purchase price you decide
to put down as a down payment.