which equation represents an exponential function that passes through the point (5,212.5) using form y=a(b)*x

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

Given a circle with measures of (c, d, and r) and a circle with measures of (c', d', and r'), what is d if c c' = 12 and d' = 0.50? a) 3 b) 6 c) 12 d) 24

One of the inventors of integrated circuits observed that the number of transistors that fit on an integrated circuit will double every 24 months. what type of relationship most appropriately models this situation?