What is the exponential function whose graph passes through (0,-20) and (2,-5)? Is this function exponential growth or decay?

Answer 1

-20 to -5 is increasing exponentially, so it's growth not decay

y=ab^2 is an exponential function

plug in (0,-20) to solve for a

-20 = a(b^0) = a(1) = a

a = -20

y=-20(b^2) plug in the other point to get

-5 =-20(b^2)

b^2 = 5/20 = 1/4

b = 1/2

the exponential equation is

y=ab^x with a= -20 and b = 1/2

y= -20(1/2)^x