For this case we have an equation of the form:
Where,
A: original price
b: growth rate
x: number of years
Substituting values we have:
Answer:
the value of the antique clock, and, in dollars, after x years is:

B - 4.2 < -7.5
subtract b and 4.2
less then sign is <
then <-7.5
Multiply 2/3 by 84 which is 56.
The number of squares on a chess or checker board is 64 and to find the square root of 64 which is 8*8=64 so the answer is 8